1. a particle A of mass 150g lies at rest on a smooth horizontal surface. a second particle B of mass 100g is projected along the surface with a speed of u m.s and collides directly with A. on collision the masses coalesce and moves on with a sped of 4 m.s . find the value of u?

Answer 1

This is a conservation of linear momentum problem.

Please show your work for further assistance. Someone here will critique your thinking.