Question

1.By what factor does the kinetic energy of a moving body change, when its speed is reduced to half?
2.What happens to mechanical energy, after ball hits the ground and comes to rest?

Answer 1

let 1/2 mv^2 = Ki

v = v/2

Kf = 1/2 m(v/2)^2
= 1/8mv^2
= 1/4 Ki

mechanical energy will be converted to heat and sound energy.