







Revolutions per minute 
20141024 

Edward pose la question : Hello; I have a 28.2 inch diameter tire; do not worry about engine RPM or gear ratios, please tell me what the RPM
of that tire is at 8 MPH and 64 MPH. Thank you.
Sincerely; Edward Penny Nom lui répond. 





Problem solving 
20140908 

hubert pose la question : a car left the house and travelled at an average speed of 60 kph.how many minutes will it take for the car to reach the school which is 8 km away from the house Penny Nom lui répond. 





A car passing a bus 
20140824 

Athish pose la question : the driver of the car is travelling at 36 km/hr and spots a bus 80 m ahead of him after 1 hr the bus is 120 m behind the car what is the speed of the bus Penny Nom lui répond. 





Distance, speed and time 
20140813 

abdel pose la question : Mac walked to a park from the college at 5 km/h. 10 minutes later, Steve started
riding his bike at 15 km/h to the same park to meet Mac. They arrive at the same
time at the park. How far is the park from the college? Tyler Wood lui répond. 





Speed, distance, time 
20140813 

Aarti pose la question : a theif running at 8 km/hr is chased by a policeman whose speed is 10km/hr.if the thief is 100 m ahead the policeman then what will b time required for the policeman to catch the thief? Tyler Wood lui répond. 





Angular speed 
20140629 

andrea pose la question : a wheel having a radius of 10cm rotates such that the linear speed at its rim is 30mls.
what is the angular speed of the wheel in rpm? Penny Nom lui répond. 





What is the speed of the buses? 
20140518 

musliu pose la question : Two buses leave a bus station and travel in opposite direction from that same starting point.if the speed of one is twice the speed of the other and they are 240km apart at the end of 1h, what is the speed of the buses? Penny Nom lui répond. 





2 cars driving towards each other 
20140427 

Joakim pose la question : 2 cars driving towards eachother , the distance between them is 162km. they meet after 2 hours. car A is driving with 4/5 of car B´s speed. what is the speed of each car... Penny Nom lui répond. 





What time was it when joe's brother passed him? 
20140425 

Nathan pose la question : joe left home in his bike at 10:00 am, traveling 21 km/h. At noon, his brother set out after him on his motorcycle, following the same route. if the motorcycle traveled at 63 km/h, what time was it when joe's brother passed him? Penny Nom lui répond. 





Walking up and down a hill 
20140206 

flo pose la question : michelle walks 4 km to the top of a hill at 3 km/h then immediately walks back down at an average speed of 5 km/h what is her average speed for the 8km walk Penny Nom lui répond. 





Why can't we add or subtract speed? 
20131121 

kashish pose la question : why we cannot add or subtract "speed" / directly in any given distance , speed , time questions? Chris Fisher lui répond. 





One train overtaking another 
20131111 

kiran pose la question : two trains of equal length are running in parallel tracks in the same direction with the speed of 60km/hr and 90km/hr respectively the latter completely crosses the former in 30 seconds the length of each train is in mtr Penny Nom lui répond. 





What is the original speed? 
20130810 

MJ pose la question : If a truck increases its average speed by 10 km/h it can cover 60 km at the original speed in the same time that it can cover 80 km at the faster speed. What is the original speed? Penny Nom lui répond. 





6 miles in 28 minutes what's my average speed? 
20130305 

lynda pose la question : 6 miles in 28 minutes what's my average speed? Penny Nom lui répond. 





Swimming upstream and downstream 
20130215 

Kimberly pose la question : a beaver swims down to its lodge 4 times faster than it swims upstream. how many times faster is its speed in still water than the speed of the stream? Penny Nom lui répond. 





A journey of two parts 
20130206 

Natalie pose la question : Mr Lim drove at 70 km per hour for 1 hour and 30 minutes. He then drove another 55 km. if his average speed for the whole journey was 80km per hour, what was his speed for the 55 km journey? Penny Nom lui répond. 





Revolutions per second 
20121018 

Crystal pose la question : Suppose a car wheel is 26 inches in diameter.
a) If the tire completes one rotation, how far would the car travel?
b) If the car is traveling at 60 miles per hour, how fast is the car wheel spinning in revolutions per second? Penny Nom lui répond. 





Adding speeds 
20120826 

Roy pose la question : May I ask if it is correct to add the following with units included? Some tell me that the units cannot be included in the addition because we cannot add speed. Harley Weston lui répond. 





A plane travelling with the wind and against the wind 
20120803 

Gwen pose la question : The time of a plane trip of 450 miles, with the wind is 3/5 the time of the return trip against the wind. If the plane travels 120 mph in still air, what is the wind speed? Penny Nom lui répond. 





How fast am i driving? 
20120518 

bozenga pose la question : How fast am I driving if I cover 40 feet in .1 seconds (1/10th of a second)? Penny Nom lui répond. 





How long will it take lee to catch up with jodie? 
20120321 

kirsten pose la question : for example, if jodie is on the bus travelling at 10 m.p.h and lee is walking at 4 m.p.h how long will it take lee to catch up with jodie?? what is this mathematical name for this Harley Weston lui répond. 





Jack and Kate set off in their cars ... 
20120213 

akiri pose la question : Jack and Kate set off in their cars from the same point to travel the same journey. Jack has a start of eight minutes before Katie sets off. If Jack travels at 50mph and Katie travels at 75mph, how many miles will be travelled when the two cars are level? Penny Nom lui répond. 





There is a police officer in pursuit of suspect 
20120201 

Jay pose la question : There is a police officer in pursuit of suspect. They suspect is driving on a straight road traveling at 79 mph, the officer is 233 yds away, traveling at 92 mph, the suspects car 5 ft long and the officers car is 5.3 ft long, how long will it take to have the front of the officers car, equal to the front of the suspects car down to the tenth of a second. Harley Weston lui répond. 





Two trains passing each other 
20111207 

Tamkeen pose la question : two trains 245m and 315m long are travelling toward each other at 90km/h and 54km/h respectively on parallel lines . how long do the train take to pass one another train the time they meet each other? Penny Nom lui répond. 





The average speed for the whole journey 
20111030 

Shahzad pose la question : a train travels 68 Km at an average speed of 51Km/h. It then travels another 20Km at an average speed of 40Km/h before reaching its destination. Calculate the average speed for the whole journey? Penny Nom lui répond. 





37 miles in 3 seconds 
20111020 

Joyce pose la question : Jake can travel 37 miles in 3 seconds,please calculate jake's rate of speed.(round to 2 decimal places) Penny Nom lui répond. 





What is the speed of the boat in still water? 
20111007 

Hannah pose la question : The speed of a stream is 3 mph. A boat travels 10 miles upstream in the same time it takes to travel 16 miles downstream. What is the speed of the boat in still water Penny Nom lui répond. 





Chuong and Hassan drive to work 
20111004 

Dilshad pose la question : Chuong and Hassan both drive 40 km from home to work each day. One day Chuong said to Hasssan, "If you drive home at your usual speed, I will average 40 kmph faster than you and arrive home in 20 minutes less time." Find Hassan's speed. Penny Nom lui répond. 





Driving to meet Mary 
20110824 

Denise pose la question : mary leaves St Paul traveling 2000 miles @ 55 MPH; John leaves LA traveling 2000 miles @ 45 MPH how many miles will John had traveled to meet mary? Penny Nom lui répond. 





Two boats 
20110329 

Mamie pose la question : Two speed boats leave the port of San Francisco traveling in opposite directions
at the same time.One boat travels 8 knots per hour faster than the other.After
one day's travel they are 1,920 nautical miles apart.What are the speeds of the
two boats. Penny Nom lui répond. 





Average speed 
20110307 

West pose la question : Calculate the distance (in km) that Larry runs if he maintains an average speed of 8km/hr for 45 minutes Penny Nom lui répond. 





What is its speed in miles per hour? 
20110106 

Miriam pose la question : An airliner travels 125miles in 15minutes. What is its speed in miles per hour? Penny Nom lui répond. 





Angular speed 
20101212 

Jason pose la question : 7 in. pulley traveling @ 175ft/sec. What is the rpm? Stephen La Rocque and Penny Nom lui répond. 





80 miles in 40 minutes 
20101208 

james pose la question : i travel 8o miles in 40 minutes. how fast am i going in mph Penny Nom lui répond. 





Angular speed 
20101203 

Julie pose la question : If the angular speed of a circle is 360 degrees divided by the time it took to rotate,
how do I calculate ones that have greater rotations than the amount of time?
I mean, you calculate the angular speed of a merrygoaround that spins once every 5 seconds
by doing 360degrees/5 sec, but how do you calculate a merrygoaround that has 16 rotations every 4 seconds? Penny Nom lui répond. 





What is its speed in still air? 
20101128 

Shelby pose la question : An Airplane flies a certain distance in 3 hours going WITH a 40km/hr wind. It travels the same distance in 5 hours when going against the wind. What is it's speed and how long would it take to travel the same distance in still air? Distance = speed x time Penny Nom lui répond. 





A train passes a car 
20101024 

Mary pose la question : A train, whose speed is 75 mph, takes 3 minutes to pass a car that is going 60 mph in the same direction. How long is the train? Stephen La Rocque lui répond. 





What are the speeds of the boats? 
20101021 

Adori pose la question : Two boats leave the port of San Francisco traveling in opposite directions at the same time. One boat travels 8 knots per hour faster than
the other. After one day's travel they are 1920 nautical miles apart. What are the speeds of the boats? Penny Nom lui répond. 





John and Mary are 200 miles apart 
20101020 

Sarah pose la question : two people, john and mary, are 200 miles apart and leave at the same time to meet.
They are driving toward each other at constant rate on the same straight road.
John is traveling at 45 mph and Mary is traveling at 35 mph.
When they meet, how many miles will they be from john's house? Penny Nom lui répond. 





A commuter airline between two cities 
20101019 

Adori pose la question : An airline runs a commuter between two cities that are 720 miles apart. If the average speed of the planes is increased by 40 miles per hour, the travel time is decreased An airline runs a commuter between two cities that are 720 miles apart. If the average speed of the planes is increased by 40 miles per hour, the travel time is decreased by 12 minutes. What airspeed is required to obtain this decrease in travel time? Penny Nom lui répond. 





Two jets leave denver at 9 am. 
20101015 

Carl pose la question : two jets leave denver at 9 am. One flying east at a speed of 50 km per hour greater than the other which is traveling west. At 11 am the planes are 2500 km apart. Find their speeds. Stephen La Rocque lui répond. 





Two cars 
20100930 

Amanda pose la question : Two cars, 142 miles apart, start moving towards each other at the same
time. One is moving 3 times as fast as the other. If they meet 1.7 hrs
later, find the average speed of the slower car in miles per hour? Penny Nom lui répond. 





What is the average speed? 
20100921 

Cindy pose la question : A boat travels downstream m nautical miles at d knots. It travels upstream m nautical miles at u knots. What is the average speed for the entire trip? Penny Nom lui répond. 





Two cars on a circular track 
20100812 

david pose la question : If two cars starts to drive at point 1 and go in a circle when will they meet?
(one cars speed is faster the other ) all I need is a formula Tyler Wood lui répond. 





How fast is the second car taveling? 
20100726 

Jeff pose la question : A car is traveling 75 mph. It takes 12 miles to overtake a second car that was .5 mile ahead. How fast is the second car taveling? Stephen La Rocque lui répond. 





Pursuing Car 1 
20100713 

Mark pose la question : Car 1 is traveling down the road at 50mph and passes Car 2 is
sitting on the side of the road. Car 2 needs to catch Car 1 one half mile
down the road. How fast must Car 2 drive to catch Car 1 if Car 2
waits 10 seconds before pursuing Car 1? Robert Dawson lui répond. 





What is the speed of the current? 
20100525 

tien pose la question : a boat travels upstream, against a current, at a speed of 4 miles per hour. On the return trip, the boat travels downstream, with the current , at 10 miles per hour. the speed of the current remains constant. what is the speed of the current? Penny Nom lui répond. 





When will the second truck catch up to the first? 
20100522 

Josie pose la question : At 9:00 a.m. a truck leaves the truck yard and travels west at a rate of 45 mi/hr. At 11:00 a.m., a second truck leaves along the same route, travelling at 60 mi/hr. When will the second truck catch up to the first? Tyler Wood lui répond. 





Find the speed of the current of the river 
20100519 

paul pose la question : a boat travels 100 miles downstream in the same length of time it travels 50 miles upstream. if the boat's speed in still water is 30 mph find the speed of the current of the river? Penny Nom lui répond. 





Sammy and his motorboat 
20100511 

Jordan pose la question : Sammy owns a motorboat that travels 4 miles/hour in still water. It goes 12 miles upstream and 12 miles back again (downstream) in a total of 8 hours. Find the speed of the current of the river. Penny Nom lui répond. 





What is the speed of the current? 
20100317 

Carl pose la question : If you can row 3 mph in still water and paddle 3 miles upstream and return in 3.6 hours then what is the speed of the current? Penny Nom lui répond. 





30.0 km per hour 
20100219 

Diana pose la question : if a car travels 30.0 km per hour, how many km will it go in 2.0 hours? How far will it go in 15 minutes? Tyler Wood lui répond. 





How fast am I walking? 
20100110 

KEVIN pose la question : IF I WALK 3 MILES IN 28 MINUTES, HOW FAST AM I WALKING? Penny Nom lui répond. 





e = m c^2 
20091209 

Jim pose la question : Please explain the following formula:
E=MC2 (squared) Robert Dawson lui répond. 





... the original speed of the car was? 
20091208 

venkatesh pose la question : A car travels a distance of 840 miles at a uniform speed if the speed of the car is increased 10 m/h more ,it takes two hours less to cover the same distance ,the original speed of the car was?
options:75 mh,65 m/h,60 m/h,55 m/h,45 m/h . Claude Tardif lui répond. 





Angular speed 
20091119 

Atalie pose la question : The engine of a sports car rotates at 5000 revolution per minute. Calculate the angular speed of the engine in radians per second, given that 2pi radians = 1 revolution Robert Dawson lui répond. 





At what rate are the people moving apart? 
20091101 

saira pose la question : A man starts walking north at 4 ft/s from a point P. 5 minutes later a woman starts walking south at 5 ft/s from a point 500 ft due east of P. At what rate are the people moving apart 15 minute after the woman starts walking ? Harley Weston lui répond. 





Two jets are traveling towards each other 
20091005 

jake pose la question : two jets are traveling towards each other and are 4000 km apart. the rate of one jet is 100 km/h faster than the rate of the other. if the jets pass each other after 2.5 hrs what is the rate of speed of the faster jet? Penny Nom lui répond. 





How fast am i going? 
20090928 

ron pose la question : how fast am i going if i drive 40 miles in 20 minutes...what is the formula for figuring this out. Leeanne Boehm lui répond. 





Average speed 
20090911 

john pose la question : Sally travels by car from one city to another. She drives for 20.0 min at 68.0 km/h, 40.0 min at 37.0 km/h, and 51.0 min at 77.0 km/h, and she spends 12.0 min eating lunch and buying gas.
What is the average speed for the trip? Penny Nom lui répond. 





Average speed 
20090820 

Christina pose la question : We ran 3.4 miles in 40 minutes. What was our average speed? Leeanne Boehm lui répond. 





Angular speed 
20090804 

Mary pose la question : The engine of a sports car rotates at 5000 revolutions per minute (rpm). Calculate the angular speed of the engine in radians per second. Use 2 radians = 1 revolution. Penny Nom lui répond. 





Driving to school and back 
20090517 

marylyne pose la question : suppose you are late for school and you drive from your house at a constant rate of 70 mph.when class is over, you drive home at a more leisurely 50mph. what is your average speed? Penny Nom lui répond. 





Two Boats 
20090516 

Simon pose la question : Two boats, one travelling towards the east and the other travelling towards the north, are 10 km apart afetr an hour. If the speed of one boat is 2 more than the speed of the other boat, what is the speed of the faster boat? Stephen La Rocque lui répond. 





What was her rate of speed? 
20090506 

Stephanie pose la question : beth paddled a canoe to a picnic spot in the river in 2 hours. she traveled up the stream back to the original spot in three hours. the current was two miles per hour.
What was her rate of speed? Robert Dawson and Stephen La Rocque lui répond. 





Two airplanes are 300 miles apart 
20090422 

afzalsultan pose la question : Two airplanes are 300 miles apart and flying directly towards each other.One is flying at 200 miles per hour, and the other at 160 miles per hour.How long will it take for the two planes to meet Robert Dawson lui répond. 





Passing three cars 
20090416 

Larry pose la question : If 3 cars are going 50 mph, and a fourth car pass the first 3 cars in 200 feet, how fast is the fourth car going? Stephen La Rocque lui répond. 





A man travels a total of 8km in 6 hours 
20090410 

Kieran pose la question : Hello!
I was wondering if you could help me with this question! Thank you
A man travels a total of 8km in 6 hours
if his speed was xkm/4hours in the first stage
then his speed was 8x/2hours in the second part.
If the average speed for the first leg of the journey
was 1.1km/h faster than the second part: find x Penny Nom lui répond. 





How many miles per hour was it traveling? 
20090404 

Regina pose la question : a car traveled 16 miles in 30 minutes. How many miles per hour was it traveling? Penny Nom lui répond. 





A trip at two different speeds 
20090328 

A student pose la question : Good afternoon!
An automobile travels 4 hours at an average speed of 42MPH. How much
longer must the truck travel at an average speed of 55MPH so the
average speed for the total trip will be 50MPH?
Thank you for your assistance! Penny Nom lui répond. 





The speed of a tire in revolutions per minute 
20090328 

Jules pose la question : Suppose that a tire on a car has an outer diameter of 2,5 feet. How many
revolutions per minute does that tire make when the car is travelling 60
miles per hour? (hint:first find the angular velocity in radians per minute.) Harley Weston lui répond. 





Fred in his canoe 
20090221 

Susan pose la question : Fred paddled for 4 hours with a 7 km/hr current to reach a campsite. The return trip against the same current took 9 hr. Find the speed of Fred's canoe in still water. (Remember to include correct units) Penny Nom lui répond. 





Catching up to the car ahead 
20090206 

Ashley pose la question : Car A passes Car B on a freeway. The driver of Car B decides to speed up to 75 mph and catch Car A, whose driver is maintaining a constant speed.
Looking ahead, the driver of Car B sees Car A go under an overpass oneqarter mile up the road. Exactly six minutes later, Car B catches Car A.
How fast was the car going? Penny Nom lui répond. 





A falling object 
20090201 

Tamara pose la question : We drop an object from rest (i.e. its initial spped is zero. It is falling freely toward the ground. What will be its speed after 5 seconds of falling? Penny Nom lui répond. 





What will be its speed after 10s? 
20090201 

Tamara pose la question : An object has an initial speed of 5 m/s and is accelerating with 2 m/s2 (m/s squared) acceleration. What will be its speed after 10s? Penny Nom lui répond. 





Linear speed 
20090126 

Hom pose la question : A semi is driving cross country at 70mph. The tires on the semi have a 3 foot diameter. What is the linear speed in feet per minute? Robert Dawson lui répond. 





The speed of the boat and the river 
20081028 

Jenn pose la question : On the Amazon River in Brazil, a boat goes 50 miles upstream in 3 hours, later the boat returns to the starting point in 2 hours. What is the speed of the boat in still water and what is the current speed in this part of the Amazon? Penny Nom lui répond. 





Finding the Speed of a Truck 
20080908 

Rita pose la question : A state trooper is hidden 30 feet from a highway. One second after a truck passes, the angle theta between the highway and the line of observation from the patrol car to the truck is measured.
(a) If the angle measures 15 degrees, how fast is the truck traveling? Express the answer in feet per second and miles per hour. Janice Cotcher lui répond. 





Angular & Linear Speed from a Sine Graph 
20080819 

Kim pose la question : Kim, a student:
I am given a graph with a wave. The amplitude is 5cm and the period is 4cm. I am suppose to find the angular speed. What I need to know is the formula for angular speed and how do I use these numbers to get the correct answer. Janice Cotcher lui répond. 





Running in opposite directions 
20080729 

maame pose la question : if i run six miles per hour and my friend runs four miles per hour and we both run for two hours in opposite directions how many miles apart will we be after the two hours? Janice Cotcher and Penny Nom lui répond. 





Going to Neptune 
20080729 

mariah pose la question : how fast would you be going per hour if you wanted to get to neptune in 1 week ? Penny Nom lui répond. 





Going from 45 mph to 35 mph 
20080709 

Terry pose la question : How long (distance  feet AND time) will it take a car traveling at 45 mph to slow down to a speed of 35 mph? Harley Weston lui répond. 





Two trains 
20080707 

Elisha pose la question : Trains at each end of the 50. km long Eurotunnel under the English Channel start at the same time into the tunnel. Find their speeds if the train from France travels 8. km/h faster than the train from England and they pass in 17 minutes. Janice Cotcher and Penny Nom lui répond. 





Miles per hour 
20080701 

Nedra pose la question : If I walk 1 mile and 2/10ths in 20 minutes how fast am I going?
AND how many calories have I burned off? Penny Nom lui répond. 





The current in a river 
20080612 

Joi pose la question : To approximate the speed of the current of a river, a circular paddle wheel with radius 4 feet is lowered into the water. If the current causes the wheel to rotate at a speed of 10 revolutions per minute, what is the speed of the current? Express your answer in miles per hour. Harley Weston lui répond. 





Can the witness' statement be correct? 
20080602 

Leria pose la question : The model S= radical 30df describes the relationship between the speed of a car , the conditions of the road, and the length of the skid marks when the car slams on the brakes. S is the speed of the car in miles per hour,
d is the length of the tires' skid marks in feet and f is the coefficient of the friction for the road.
In an accident, a car makes skid marks 85 feet long. The coefficient of friction is 0.6. A witness says that the driver was traveling faster than the speed limit of 35 miles per hour. Can the witness's statement be correct? Use algebra to explain your answer. Penny Nom lui répond. 





A cat is walking on the tread of a tank 
20080526 

Kathleen pose la question : If a cat is walking on the tread of a tank travelling at 28kmh how fast does the cat have to walk to avoid falling under the tracks? Janice Cotcher lui répond. 





What is the altitude of the plane? 
20080423 

tiana pose la question : If a plane is taking off and its climbing at 380 feet per minute at 205 MPH, what is the altitude of the plane after it traveled 115 miles? Penny Nom lui répond. 





A car is travelling at 80 km/hr speed 
20080410 

mathew pose la question : A CAR TRAVELLING AT A SPEED OF 80km/hr. How much time will take this car to cross a tunnel of 100M Penny Nom lui répond. 





1 mile per minute 
20080401 

jennifer pose la question : If you are traveling at 1 mile per minute how fast would you need to be going Stephen La Rocque lui répond. 





A train and a boat 
20080315 

Sabrina pose la question : A railroad bridge is 20m above, and at right angles to, a river. A person in a train travelling at 60 km/h passes over the centre of the bridge at the same instant that a person in a motorboat travelling at 20km/h passes under the centre of the bridge. How fast are the two people separating 10s later? Harley Weston lui répond. 





Average speed up and down a hill 
20080309 

Judith pose la question : An old brokendown ar has to travel a two miles route, up and down a hill.
Because it is so old, the car travels the first mile  the ascent  at an average
speed of fifteen miles per hour. How fast must it cover the second mile 
the decent  to achieve an average speed of thirty miles per hours?
(There is a missing variable, but what is it?) Penny Nom lui répond. 





A ball bearing is placed on an inclined plane 
20080215 

Leah pose la question : A ball bearing is placed on an inclined plane and begins to roll.
The angle of elevation of the plane is x.
The distance (in meters) that the ball bearing rolls in t seconds is s(t) = 4.9(sin x)t^2.
What is the speed of the ball bearing,
and what value of x will produce the maximum speed at a particular time? Penny Nom lui répond. 





Radians 
20080208 

Brian pose la question : I'm teaching Precalculus right now and will be covering the formula to convert angular speed into linear speed. My question is about the units involved. Using v=rw, if r is mearsured in feet and w is measured in radians/second then v is measured in ft/sec. What happened to the units of radians? I can't find a good way to explain why they are not part of units for velocity. Do you have a good explanation?
Thanks, Stephen La Rocque lui répond. 





Driving towards each other 
20080116 

Shanda pose la question : Paul and Charlene are 420 miles apart. They start toward each other with Paul driving 16 miles per hour faster than Charlene. They meet in 5 hours. Find Charlene's speed. Stephen La Rocque lui répond. 





What is the speed of the plane in still air? 
20080105 

oscar pose la question : A plane flies 400 miles with the wind and 340 miles against the wind
in the same length of time. If the speed of the wind is 24mph, what is
the speed of the plane in still air? Penny Nom lui répond. 





How many complete revolutions does each wheel make? 
20071228 

varoon pose la question : The wheels of a car are of diameter 80cm each. How many complete revolutions does each wheel make in 10 minutes when the car is travelling at a speed of 66kms per hour? Penny Nom lui répond. 





Two cars going in opposite directions 
20071125 

alexa pose la question : two cars leave town at the same time going opposite directions. one of them
travels at 55 mph and the other at 65 mph. in how many hours will they be
150 miles apart? Penny Nom lui répond. 





Radial motion 
20071113 

abdulai pose la question : a circular saw with diameter 18.4cm rotates at 2400rpm. What is the angular speed of a point on the edge of the saw blade in radians per second? Penny Nom lui répond. 





Stopping distance and speed 
20071111 

Joanna pose la question : The algebraic relation d=0.0056^2 ++ 0.14s models the relation between a vehicle's stopping distance d, in metres, and its speed s, in kilometres per hour.
(a) What is the fastest you could drive and still be able to stop within 80 m?
(b) What is the stopping distance for a car travelling at 120 km/h?
(c) Estimate the length of an average car. How many car lengths does the the stopping distance in (b) correspond to? Stephen La Rocque lui répond. 





A car traveled 175m at certain speed 
20071028 

abdi pose la question : A car traveled 175m at certain speed. if the speed had been 20 mph faster,
the trip could have been made in 1 hr less time. find the speed? Stephen La Rocque lui répond. 





Two cars 
20070917 

Lanie pose la question : Two cars enter the Florida Turnpike at Commercial Boulevard at 8:00am, each heading for Wildwood. One car's average speed is 10 miles per hour more than the other's. The faster car arrives at Wildwood at 11:00 am, 1/2 hour before the other car. What is the average speed of each car? How far did each travel? Stephen La Rocque lui répond. 





How many miles per hour was I driving 
20070911 

Gary pose la question : How many miles per hour was I driving to go 37 miles in 13 minutes Victoria West lui répond. 





Speed of sunrise 
20070904 

Robert pose la question : Facing west in a car, you are watching the sun rise (through the rear view mirror). It peaks the horizon, you take off driving. How fast would you have to drive, to see it rise again? Stephen La Rocque lui répond. 





Angular speed 
20070805 

Virginia pose la question : the engine of a sports car rotates at 5,000 revolutions per minute (rpm). calculate the angular speed of the engine in radians per second. use 2n radians = 1 revolution Stephen La Rocque lui répond. 





A quarter of a mile in eight seconds 
20070629 

Kevin pose la question : What speed is a vehicle traveling if he drove a quarter of a mile in eight seconds? Harley Weston lui répond. 





Average speeds 
20070622 

Dee pose la question : A guy goes 3.1m a second for 29 seconds in a golf cart. He then walks 1.5 meters a second. How long does he have to walk to get the average speed of 2.1m a second? Stephen La Rocque lui répond. 





How fast was he going? 
20070603 

Mary pose la question : if a motorcycle left a 63 foot skid mark before hitting a car how fast was he going ? Penny Nom lui répond. 





Converting speeds 
20070510 

jason pose la question : A boy runs 36 metres in 6.50 seconds.How fast is he going in miles per hour Stephen La Rocque lui répond. 





A tugboat's speed 
20070430 

Amanda pose la question : a tugboat must travel 24 miles against a 4 mile per hour current on the Potomac River and return. At what
constant speed must the tugboat travel to make the trip in 12 hours. Round answer to the nearest tenth mph. Stephen La Rocque lui répond. 





What is the speed of the boat? 
20070422 

Sonja pose la question : A boat on a river travels downstream between two points, 20 miles apart, in one hour. The return trip against the current takes 2 1/2 hours. What is the speed of the boat? The answer in the book says 14 mi/hr, but I don't understand how to figure it out. It must be very simple, but I'm stuck. Thank you so much for helping me out. This is a FANTASTIC website! Sonja Penny Nom lui répond. 





The second derivative 
20070414 

Gerry pose la question : In mathematical context,what do you understand by the term "Second Derivative" Penny Nom lui répond. 





When will the rocket hit the ground? 
20070405 

Megan pose la question : A model rocket is launched at an upward velocity of 460feet per second off a platform that is 40 feet up from the ground. Use the formula h(t)= 16+vo+ho where vo is the initial velocity an ho is the initial height.
A.) Find the maximum hight of the rocket.
B.) How long does it take to reach the maximum height?
C.) When will the rocket hit the ground? Stephen La Rocque lui répond. 





Velocity 
20070404 

Jessica pose la question : The speed of the current in a river is 2mph. Jessica travels 20 miles upstream and then 20 miles downstream in a total time of 5 1/3 hr. Find the speed of the boat.
I know you have to use V= d/t, but what is the equation for time because you have to factor in that upstream the boat is slower and downstream the boat is faster? Penny Nom lui répond. 





A delivery driver travels from Belfast to an address in Dublin 
20070404 

Gerry pose la question : A delivery driver travels from Belfast to an address in Dublin.The total distance fro the round trip
was x%.The time required for the forward trip was xx hours.Due to heavy traffic during the return trip an extra xx was required
How much slower was the delivery drivers speed on the return trip?.
I was wondering what equation would you use to solve this question. Penny Nom lui répond. 





Boat trigonometry 
20070404 

Kimi pose la question : Hi,
I have been working on the attached math problem for my college trig class for over a week. Every avenue I've tried seems to lead either to a dead end, an unreasonable answer, or extremely complicated computations. I was able to calculate the speed of the boat to 3.51 mph, but cannot figure out the measure of angle beta. Once I can figure that out, I can do the rest of the problem.
Thanks,
Kimi Stephen La Rocque lui répond. 





Tina swims 4 miles upstream at 1 mph 
20070331 

Michael pose la question : If Tina swims 4 miles upstream at 1 mph and back downstream to the same point to the same point at 4 mph, what is her average speed? Penny Nom lui répond. 





A beam on a lighthouse 
20070328 

Lisa pose la question : A beam on a lighthouse 2000 metres away from the nearest point P on a straight shoreline revolves at the rate of 10 pi radians per minute. How fast is the beam of the light moving along the shoreline when it is 500 metres from P? Stephen La Rocque lui répond. 





Approximate average speeds 
20070319 

Anne pose la question : A bicyclist pedaled up a 2 mile long hill averaging 4 miles per hour. Upon reaching the top, the bicyclist headed down a 6 mile descent averaging 26 mph. What was the bicyclist's approximate average speed?
Thanks very much in advance!! Stephen La Rocque and Penny Nom lui répond. 





How long does she have to get out of the way? 
20070223 

Sharon pose la question : How do I solve this? The height h (in feet) of an object that is dropped from the height of s feet is given by the formula h = s  16t^2 , where t is the time the object has been falling. A 6 foot tall woman on a sidewalk looks directly overhead and sees a window washer drop a bottle from the 6 story. How long does she have to get out of the way? Round to the nearest tenth. (A story is 12 feet.) Penny Nom lui répond. 





Increasing speed and decreasing time 
20070218 

Nigel pose la question : I am completely lost...can you help with this: The time, t, to travel a distance, d, at a constant speed, v, can be obtained from the formula: d = vt. If the speed is increased by x, find an expression to represent the decrease in time to travel the same distance. Stephen La Rocque lui répond. 





A gymnast is swinging on a high bar. 
20070214 

William pose la question : A gymnast is swinging on a high bar. The distance between his waist (center of mass) and the bar is 1.1 m. If his speed at the top of his swing is zero and his gain in speed is due entirely to his change in gravitational potential energy, find his speed at the bottom of his swing. Stephen La Rocque lui répond. 





A person jumps from the roof of a house 
20070213 

Jessie pose la question : A person jumps from the roof of a house 3.9m high. When he strikes the ground below, he bends his knees so that the torso decelerates over an approximate distance of 0.70m. If the mass of his torso (excluding legs) is 42kg, find a) his velocity just before his feet strike the ground , and b) the average force exerted on his torso by his legs during deceleration.
Please provide calculations and answers for comparison. Stephen La Rocque lui répond. 





Driving on a banked roadway 
20070205 

William pose la question : A race track is shaped like an inverted cone. Race cars drive around this track in a horizontal path. If a drivers speed is 34 m/s, at what distance from the tip of the cone should he drive his car if there is no friction?
THANKS IN ADVANCE FOR ANY ASSISTANCE YOU CAN PROVIDE!
Sincerely, William Bush Stephen La Rocque lui répond. 





Freefalling objects 
20070125 

Patricia pose la question : How long will it take a stone dropped from atop a 1000meter tall building to reach the ground? Stephen La Rocque lui répond. 





A college student jogs from his home to the beach 
20070123 

Garmani pose la question : A college student jogs from his home to the beach at 8 miles per hour. He visits with his friends on the beach for 4 hours, and then his friends drive him home at the rate of 40 miles per hour. If the student returns home after 6 hour, what is the distance from his home to the beach? Penny Nom lui répond. 





What is the speed of each boat per hour? 
20070122 

Garmani pose la question : Two tuna boats leave the same port traveling in opposite directions along the west coast of the United States. One boat travels 5 miles per hour faster than the other. At the end of one day's travel they are 1,080 miles apart. What is the speed of each boat per hour? Penny Nom lui répond. 





Angular speed 
20070118 

Cristina pose la question : A car is moving at a rate of 50 miles per hour, and the diameter of its wheels is 2.5 feet. a) Find the number of revolutions per minute the wheels are rotating. b) Find the angular speed of the wheels in radians per minute. Stephen La Rocque lui répond. 





At what speeds were they travelling? 
20070116 

Maria pose la question : Kim and Julie are joining Nicole at her parents cottage for the weekend. The cottage is 150km away from their neighbourhood. Kim can leave directly after school but Julie will be leaving after band practice, an hour and a quarter later. Kim took her time and drove slowly, averaging 20km/h slower than Julie. They both arrived at the same time. At what speeds were they travelling? Stephen La Rocque lui répond. 





What is his rate of walking for the entire trip? 
20070112 

Garmani pose la question : A man walks 500 feet at 4 miles per hour and returns to the starting point at 3 miles per hour. What is his rate of walking for the entire trip? Stephen La Rocque lui répond. 





Throwing a stone downwards 
20070112 

Momo pose la question : a stone is thrown vertically downward with an initial speed of 14m/s from a height of 65 m above the ground. A) how far does the stone travel in the first 2.0 s? B) what is the stone velocity just before it hits the ground? Stephen La Rocque lui répond. 





What is the speed of the current? 
20070107 

Bob pose la question : A motorboat can maintain a constant speed of 16 miles per hour relative to the water. The boat makes a trip upstream to a certain point in 20 minutes; the return trip takes 15 minutes. What is the speed of the current? Haley Ess lui répond. 





Angular speed 
20070106 

Robert pose la question : A rear wheel and tire on a John Deere 8520 farm tractor has a 39in. radius. Find the angle (in radians) through which a wheel rotates in 12 sec if the tractor is traveling at a speed of 22 mph. Penny Nom lui répond. 





The Metra and the Amtrack 
20061203 

Amy pose la question : A Metra commuter train leaves Union Station in Chicago at 12 noon. Two hours later, an Amtrak train leaves on the same track, traveling at an average speed that is 50 miles per hour faster than the Metra train. At 3PM the Amtrak train is 10 miles behind the commuter train. How fast is each going? Stephen La Rocque and Penny Nom lui répond. 





A trip on the Grand River 
20061130 

Kristy pose la question : Romo decided to make a 28km trip up and 28km trip down the Grand River. the speed of the current is 3km. one way Romo travelled with the current and the other way against the current. During his trip, Romo stopped for half an hour for lunch. if Romo's total trip lasted 6hours, how fast did he travel? Stephen La Rocque lui répond. 





How high is the satellite above the earth? 
20061113 

Naomi pose la question : If the linear speed of a satellite in synchronous orbit is 1000 mi/h, how high is the satellite above the earth? Stephen La Rocque lui répond. 





Angular speed 
20061004 

Jack pose la question : A horse on a merrygoround is 7m from the center and travels at a speed of 10km/h. What is its angular speed? Stephen La Rocque lui répond. 





How long will it be before the two snails meet? 
20060921 

Brett pose la question : Two snails are 8.5 feet apart. They start to crawl toward each other at the same time. One of them travels at the speed of 6 in. per minute, while the other zips along at 11 inches per minute. How long will it be before the two snails meet? Penny Nom lui répond. 





Speed of a four wheeler 
20060814 

Luke pose la question : My question is, i race four wheelers on weekends and was trying to find out how fast we are going i race 500 ft.in about 6.00 seconds .how do you figure out the speed i am traveling? Penny Nom lui répond. 





A point on a bicycle rim 
20060801 

Sonu pose la question : Find the speed in m/s of a point on a bicycle rim of diameter 88cm making 200 revolutions per minute. Penny Nom lui répond. 





Flying with and against the wind 
20060706 

Tim pose la question : When a plane flies with the wind, it travels 800 miles in 4 hours. Against the wind it takes 5 hours to cover the same distance. Find the rate of the plane in still air and the rate of the wind. Stephen La Rocque lui répond. 





A boat travels 60 miles upstream ... 
20060528 

Teenarick pose la question : A boat travels 60 miles upstream against the current in 3 hours. It takes 2 hours for the return trip. Find the speed of the boat in still water. Penny Nom lui répond. 





An aircraft going from city A to city B 
20060510 

Preston pose la question : An aircraft going from city A to city B on a bearing of S69 degrees East is traveling at a speed of 430 mph. The wind is blowing out of the north to south at a speed of 25 mph. Find the ground speed and the plane's true bearing. Stephen La Rocque lui répond. 





How far from Earth is Neptune? 
20060321 

Scott pose la question : A laser beam travelling at the speed of light bounces off the planet Neptune and returns to Earth in 29 960.72 s. The speed of light is 299 792.5 km/s. How far from Earth is Neptune? Penny lui répond. 





Find the ground speed and the planes true heading. 
20060205 

Jimmie pose la question : An aircraft going from city A to city B on a bearing of S69E (degrees) is traveling at a speed of 430 mph. The wind is blowing out of the north to south at a speed of 25 mph. Find the ground speed and the planes true heading. Penny Nom lui répond. 





Speed on a bicycle 
20050727 

Deborah pose la question : We are trying to figure out how many miles per hour we rode in a bike race. If the distance was l5 miles and the time it took was was 55 minutes, what is the speed? Penny Nom lui répond. 





An aircraft is flying directly from airport A to airport B 
20041022 

A student pose la question : In this question, i is a unit vector due east and j is a unit vector due north. An aircraft is flying directly from airport A to airport B, which is 2000 km from A. The velocity in still air of the aircraft is (150i+50j)km/h and the ground speed is (200i30j)km/h. Calculate
(i) the time of flight, to the nearest min
(ii) the direction of the wind. Penny Nom lui répond. 





Accelerating to the speed of light 
20040930 

Lars pose la question : How long time would it take to accelerate up to the speed of light with an acceleration speed similar to 0100 seconds in 5 seconds? Penny Nom lui répond. 





The commuter 
20040714 

JJ pose la question : A student who commutes 27 mi. to college remembers, after driving a few minutes, he forgot a term paper. Driving faster than usual, he returns home, gets the paper, and once again starts to school. Sketch the graph of the student's distance from home as a function of time.
Does it mean that the student drives at normal speed, drives faster to pick up the paper, and resumes normal speed to head back, or that the student drives at normal speed, then drives faster the rest of the way to college? Penny Nom lui répond. 





Angular speed 
20040201 

Rachel pose la question : A 4 inch pulley on a motor makes 1500 revolutions/minute. It is connected to an 8 inch saw blade.
a. Find the angular speed of the pulley in radians/minute
b. Find the angular speed of the saw in radians/ minute
Harley Weston lui répond. 





The London marathon 
20040127 

Nina pose la question : After a years training, Minnie Midriffe increased her average speed in the london marathon by 25%. By what percentage did her time decrease?o Penny Nom lui répond. 





What is the speed of the automobile? 
20040120 

Rita pose la question : An automobile travels toward Nashville from Cookeville. It takes 33 minutes to travel from Cookeville to Manchester, which is a 36 mile distance. If the driver continues at this pace, what is the speed of the automobile? Penny Nom lui répond. 





A rock on a string 
20031026 

A student pose la question : a rock on a 4' string is rotated at 80 rpm. what is the linear speed in feet per second? in miles per hour? Penny Nom lui répond. 





A boat travels 12 km upstream... 
20030903 

Sohaib pose la question : A boat travels 12 km upstream and back in 1 hour 45 minutes. If the speed of the current is 3km/hr throughout, find the speed of the boat in still water, giving your answerÝcorrect to 3 decimal places. Penny Nom lui répond. 





A helicopter rises vertically 
20030902 

Kate pose la question : A helicopter rises vertically and t seconds after leaving hte ground its velocity is given in feet per second by v(t) = 8t + 40 / (t+2)^{2} How far above the ground will the helicopter be after 3 seconds? Penny Nom lui répond. 





A radio controled car 
20030608 

Robert pose la question : I have a radio controled car (scale size 1/43). This car can travel 490 ft. per minute. I would like to know how fast that is at that scale size in miles per hour (and Kilometers per hour)? Penny Nom lui répond. 





Two rate problems 
20020930 

Rebecca pose la question :
 There are two small holes in the bottom of a tub filled with water. If opened, one hole will empty the tub in three hours; the other will empty it in six hours. If both holes are opened at the same time, how long will it take to empty the tub?
 An airplane flies 400 miles per hour in calm air. It can cover 900 miles flying with the wind in the same time that it can cover 700 miles against the wind. What is the speed of the wind?
Penny Nom lui répond. 





Flying with the wind 
20020519 

SaraJean pose la question : It takes 6 hours for a plane to travel 720 km with a tail wind and 8 hours to make the return trip with a head wind. Find the air speed of the plane and the speed of the wind current. Penny Nom lui répond. 





A test drive 
20020423 

Jennie pose la question : At 9 A.M. a test car driving at a constant speed passes a marker 50 miles from it's starting point. At noon the car is about 130 miles from the marker. If the test drive ends at 1:30 P.M., how far will the car be from its starting point? Penny Nom lui répond. 





Mr. Byrd's drive to work 
20020322 

Mr. Bollen pose la question : Mr. Byrd leaves his house at 7:00am to go to work. If he drives 40 mph he will arrive 3 minutes late and if he drives 60mph he arrives 3 minutes early. At what speed will Mr. Byrd have to drive in order arrive exactly on time. Please describe how you arrived at your answer. Claude Tardif and Penny Nom lui répond. 





How far does the fly fly? 
20010807 

Harold pose la question :
6 MPH 4 MPH
Rachel  Eli
10 Miles apart
The fly is on Rachels handlebars. The fly is scared so it flys back and forth at 20 MP H. How far has the fly flown when Rachel and Eli meet? f Penny Nom lui répond. 





The speed of the boat 
20010712 

Sharon pose la question : A motor boat is travelling in a southeasterly direction in water that is flowing from the south at 2km per hour. Show that the speed of the boat is (6 times the square root of 2) km per hour, given that it can travel at 10km per hour in still water. Penny Nom lui répond. 





Average speed 
20010501 

Tom pose la question : A ship goes in one direction, west to Hawaii, at 20 nautical miles per hour and, because of the wind, makes the return trip at 30 nautical miles per hour. What is the average speed? Claude Tardif lui répond. 





Processing speed 
20010126 

Zac pose la question : A COMPUTOR IS ADVERTISED AS HAVING A PROCESSING SPEED OF 11 MILLION INSTRUCTIONS PER SECOND. ON THE AVERAGE, HOW LONG DOSE IT TAKE TO PROCESS ONE INSTRUCTION AT SUCH A SPEED? Leeanne Boehm lui répond. 





Cincinnati to WinstonSalem 
20010123 

Belinda pose la question : Joan Bedney travels from Cincinnati to WinstonSalem at an average rate of 40 miles per hour and returns at an average rate of 60 miles per hour. What is her average speed for the trip? Leeanne Boehm and Claude Tardif lui répond. 





Gravity 
20000906 

Robert Broomfield pose la question : If they dropped a 1lb object from 40,000 feet in the air, at what speed would it it the ground? Harley Weston lui répond. 





The speed of light 
20000619 

Benny Lau pose la question : I have a personal questions. In physics,if a person is running on a train, his relative speed on the ground will be the addition of the speed of train and the person. If u have a train inside another train and inside another train, so on...... can u reach the speed of light? It would need a very long distance. But if we make all the train travel in circles. Then we don't need that much distance. So can we achieve the speed of Light? Robert Coleman and Harley Weston lui répond. 





Running Through a Train Tunnel 
20000401 

Eugene Chan pose la question : A man is running through a train tunnel. When he is 2/3 of the way through, he hears a train that is approaching the tunnel from behind him at a speed of 60 mph. Whether he runs ahead or back, he will reach an end of the tunnel at the same time the train reaches that end. At what rate, in miles per hour, is he running? (Assume he runs at a constant rate.) I think the answer (12 mph) is wrong. Also, I believe it should read 1/3 of the way through, but don't know how to prove it. Could you come up with some way to prove it, please? I would really appreciate it. Penny Nom lui répond. 





Word problems 
20000331 

Amy pose la question : Question:  a north bound train left at noon. four hours later a south bound train left the same station. at 5 o'clook they were 160 miles apart. what was the rate of both if the north bound train was going 20 miles faster than the other one.
 clark's final exam was given 5 times the weight of the weight of a weekly test. the avgerage of 15 weekly test was 91. the overall weighted average was 85. what did he make on the final.
Penny Nom lui répond. 





Travelling from A to B 
20000320 

Matt pose la question : A car is traveling from point A to point B. Point A and point B are 30 miles apart. A car travels 30 miles an hour from point A to point B and then goes back to point A. How fast does the car have to go back to average 60 miles an hour? Claude Tardif lui répond. 





A bike race 
19990423 

Bill Gepford pose la question : Bill was in a bike race and his friend kyle calculated that if he went 15mph that he would cross the noontime checkpoint one hour early but if he rode 10mph he would arrive one hour late. How far away is the checkpoint? Penny Nom lui répond. 





Rowing on the Charles River. 
19970917 

Fawwaz Muraisi pose la question : On the Charles River in Boston, the Harvard bridge and the Longfellow bridge are 1 mile apart. The MIT crew starts rowing upstream at the Longfellow bridge. As the crew passes under the Harvard bridge, the coxswain's hat falls into the river. Ten minutes later, the coxswain notices and turns the boat around instantaneously. He has t he crew row back to get it, rowing at the same constant rate. By the time the team reaches the hat, they are back at the Longfellow bridge.How fast is the river flowing? Harley Weston lui répond. 

