A 131 kg car is at rest at the top of a 39 m high hill. If the car rolls down a frictionless hill, how fast will it be moving when it reaches ground level?

1 Answer
Andrea B.
Jun 13, 2018

27,6 m/s

Explanation:

The potential energy of the car (mgh) will become kinetic energy at the ground level (#1/2 mv^2#)
# m xx g xx h = 1/2 xx m xx v^2#
if you neglet the friction of ground and of air it not important the mass
# g xx h = 1/2 xx v^2#
so, you can obtain the velocity
# v = sqrt( 2g xx h) = sqrt (2 xx 9,8 m/s^2 xx 39 m) =27,6 m/s#

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