Answered

A 2 kg ball is released from rest at the top of a track and

reaches a speed of 10 mls at the bottom.

AHow much kinetic energy does the ball have?
BHow much potential energy did it have at the top of

t

hill (assuming no energy was lost?

CWhat was the height of the hill?

A 2 kg ball is released from rest at the top of a track and reaches a speed of 10 mls at the bottom. a. How much kinetic energy does the ball have? b. How much class=

Verified Answer :

AThe formula for kinetic energy is E = 1/2 mv^2, so the energy of the ball is 1/2 2 10^2 = 100J.
BEnergy is always conserved, and so if no energy is lost to resistive forces then all 100J of kinetic energy came from its potential energy at the top of the track.
CThe formula for potential energy is E = mgh, which we can rearrange for h = E/mg. We know the energy, the mass and the strength of gravity, so we can find h = 100 / (2*9.81) = 5.10m.

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