A frictionless track is to be built as shown, with L=3.70m and H=3.50m. In order to get the cart to slide from

Question

A frictionless track is to be built as shown, with L=3.70m and H=3.50m. In order to get the cart to slide from the top to the end of the track in the minimum time, how long should the distance D be? Assume that the speed of the cart on the horizontal surface is the same as at the bottom of the ramp.

here is the picture that goes along with this question
http://capa-new.colorado.edu/msuphysicslib/Graphics/Gtype11/prob05_ramp2.gif
thanks!!

kingswan, that is what i thought too, but it is not the right answer..

thanks anyway

Answer 1

perhaps D should be incredibly short so the cart simply falls. this would cause most of the energy to be absorbed by the impact and the cart would then move slowly to the end of the track.

Answer 2

thats not too bad, the best angle you want to make is a 45 degree angle, so you want D to equal L so 3.7 m. a 45 degree angle always gives you the best trajectory, and go ahead and try out lengths around that number and you will see that they would give higher times.

anything higher than 45 degrees gives you a greater velocity, but a longer distance to travel, anything less gives you a lower velocity and a shorter distance but at 45 it gives you the right answer.

D = 3.70

Answer 3

physics sucks