Question

How much work is needed to be done on a ball of mass 50 g to give it a momentum of 5 kg cm s^-1?

Answer 1

Kinetic energy is related to momentum as

K.E. where K = `p^2/(2 m)` and p is the momentum of the body

K.E. is nothing but work done

∴ K.E. = Work done = `("momentum")^2/(2 xx "mass of body")`

= `(5)^2/(2 xx (50/1000))`

= `(5 xx 5)/(2 xx (1/20))`

Work done = `25/(1/10)`

= 25 × 10

= 250 J