Question

A ball of mass 1kg moving with a velocity of 15m`//`s undergoes a head on elastic collision with another ball of unknown mass at rest, and rebound with a velocity of `10m//s`. What is the mass of the other ball?

Answer 1

Here, `m_(1)=1kg, u_(1)=15m//s, m_(2)=? U_(2)=0,v_(1)=-10m//s`
In a head on elastice collision, `v_(1)=((m_(1)-m_(2))u_(1))/(m_(1)=m_(2)) or -10=(1-m_(2))/(1+m_(2))15`
or ` -10-10m_(2)=15-15m_(2) or 15m_(2)-10m_(2)=15+10`
or `m_(2)=(25)/(5)=5kg`