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	Calculer la hauteur de chute de cette pierre		2000-12-16
		Marcus pose la question : Une pierre tombe au fond d'un puit, à 5 secondes on entend un son (de la pierre). Calculer la hauteur de chute de cette pierre en tenant compte de la vitesse du son = 340m.s-1 Il faut savoir que pour la chute libre v= g.t ; h = 1/2 g.t2 ; v = 2g.h g intensité du champs de pesanteur = 10 ; h hauteur de chute. Claude tardif lui répond.
	Stefan-Boltzmann Law		2009-12-28
		florence pose la question : Hi- I have a college tutor and we are stumped with this question. Assuming a filament in a 100 W light bulb acts like a perfect blackbody, what is the temperature of the hottest portion of the filament if it has a surface area of 6.3 X 10^-5 m^2? The Stefan-Boltzmann constant is 5.67 X 10-4 W/(m^2 X K^2.\ Thank you for your help. If you can only answer one question per day please answer this one and guide me through a solution. Janice Cotcher lui répond.
	Finding Specific Heat of a Substance		2009-12-26
		erin pose la question : Hi- 2 kg metal requires 1.00 X 10^4 J of heat to raise its temperature from 20 degrees C to 40 degrees C. What is the specific heat capacity of the metal? Janice Cotcher lui répond.
	Initial Velocity of a Car Plunging Off a Cliff		2009-06-07
		Mimi pose la question : A car fails to take a sharp turn on a flat road and plunges off a cliff. The car lands 65m horizontally and 43m vertically from where it left the edge of the cliff. How fast was the car travelling? Stephen La Rocque lui répond.
	Find the resultant of this displacement pair		2009-02-22
		katydidit pose la question : Find the resultant of this displacement pair: 500 miles at 75 degrees east of north and 1500 miles at 20 degrees west of south. How do I graph this and how do I solve this problem? Penny Nom lui répond.
	A falling block		2008-10-18
		KOBINA pose la question : A 50 kg block being held at rest 20m above the ground is released. the block falls (no friction). how fast is the block traveling (in m/sec) when it has lost 40% of its original potential energy. Stephen La Rocque lui répond.
	Balancing on a fulcrum (net torque and equilbrium)		2008-01-15
		Eric pose la question : If I have a 4" bar that has no weight value with a 275lb. weight on one side and a 125lb. weight on the other side what would be the folcrum point? Please keep the answer very simple. Also is there a fixed equation to figure folcrum points? Is there an equation for if the 4" bar had a weight value? Stephen La Rocque lui répond.
	Constantly accelerated motion		2007-10-29
		Priyanka pose la question : A, B and C are three points lying in that order on a straight line. A body is projected from B towards A with speed 3 m/s. The body experiences an acceleration of 1 m/s^2 towards C. If BC =20 m, find the time taken to reach C and the distance travelled by the body from the moment of projection until it reaches C. Stephen La Rocque lui répond.
	Average speeds		2007-06-22
		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.
	A couch sliding off a truck		2007-04-30
		William pose la question : A couch with a mass of 1 X 10^2kg is placed on an adjustable ramp connected to a truck. As one end of the ramp is raised, the couch begins to move downward. If the couch slides down the ramp with an acceleration of .70 meters per second when the ramp angle is 25 degrees, what is the coefficient of kinetic friction between the ramp and couch? I drew a force diagram and if I did it correctly I identified the forces involved as "mg" (mass x gravity), "Fn" (normal force) and the "Ff" (frictional force). I know that we have the couch sliding down the ramp a .70 m/s but I don't think this a force and I'm not sure how this info fits into the problem. I know that the formula for calculating the coefficient of friction is Ff/Fn. Based upon the force diagram I drew and calculated Fn to be 1082N. I can't seem to get past this point. How do I determine what the frictional force is? Stephen La Rocque lui répond.
	Rotor-ride		2007-03-07
		Jessie pose la question : In a "Rotor-ride" at a carnival, people are rotated in a cylindrically walled "room". The room radius is 4.6m and the rotation frequency is 0.550 revolutions per second when the floor drops out. What is the minimum coefficient of static friction so that people will not slip down? People on this ride say they were "pressed against the wall". Is there really an outward force pressing them against the wall? If so, what is its source? If not, what is the proper description of their situation (besides scary)? Stephen La Rocque lui répond.
	A gymnast is swinging on a high bar.		2007-02-14
		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.
	Driving on a banked roadway		2007-02-05
		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.
	Static electricity on an airplane		2000-11-12
		John pose la question : What discharges an airplane of static electricity in a electric storm when it is flying. I assume the charge is on the out side of the plane but when does it get discharged, or does it occur at landing? Ted Mathie lui répond.

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