Question

7) A 2 kg cart rolls down a frictionless ramp. It starts with 58.8 J of energy at the top of the ramp. How fast would the cart be moving when it is halfway (in height) down?​

Answer 1

The problem is asking one to assume that the potential energy at the top of the ramp is 58.8 J and the potential bottom is zero:

then 1/2 m v^2 = 29.9 J or 1/2 the energy - one cannot solve for v without knowing a value for KE

v^2 = 58.8 / 2 = 29.9

v = 5.47 m/s

(if the cart had any KE at the top of the ramp then one cannot solve the problem because the speed of the cart is not defined)