Question

A body of mass `1.5kg` moving with a velocity of `10m//s` encounters another body of mass `2.5kg` moving in opposite direction with a velocity of `16m//s`, and they stick to eachother. What is the velocity of combination?

Answer 1

Here, `m_(1)= 1.5kg, u_(1)= 10m//s`
`m_(2)= 2.5kg, u_(2)=16m//s`
`v=?`
Applying the principle of conservation of linear momentum,
`(m_(1)+m_(2))v=m_(1)u_(1)+m_(2)u_(2)`
`v=(m_(1)u_(1)+m_(2)u_(2))/(m_(1)+m_(2))= (1.5xx10+2.5(-16))/(1.5+2.5)= (-25)/(4.0)= -6.25m//s`
Negative sign indicates that motion of combination of bodies is along the direction of motion of second body.