Croquet ball A moving at 8.0m/s makes a head on collision with ball B of equal mass and initially at rest. Immediately after the collision ball B moves forward at 7.1m/s .

Question

What fraction of the initial kinetic energy is lost in the collision?

Answer 1

initial Ke calculate
final Ke, calculate

ke lost=initial-final

fractction lost=kelost/keinitial

Answer 2

(-2(vb)^2+2(va+vb))/va^2
where
va is first velocity and
vb is 2nd given velovty