Question

A 3.0-kg cart rolls down a hill. Assume that the height of the cart changes from a maximum of 4.0 meters at the top of the hill to 0.0 meters at the bottom. The speed of the cart changes from 0.0 m/s to 3.0 m/s. How much kinetic energy does the cart have when it is half-way down the hill?

A) 6.0J
B) 12.0J
C) 58.8J
D) 117.6J

Answer 1

C) 58.8 J

Step-by-step explanation:

Initially, the cart has only potential energy.

PE = mgh

PE = (3.0 kg) (9.8 m/s²) (4.0 m)

PE = 117.6 J

Halfway down the hill, half the potential energy has been converted to kinetic energy.

KE = 117.6 J / 2

KE = 58.8 J