BITSAT2012PhysicsCenter of Mass, Momentum and CollisionActual
A man of mass 100 ~kg . is standing on a platform of mass 200 ~kg . which is kept on a smooth ice surface. If the man starts moving on the platform with a speed 30 ~m / sec relative to the platform then calculate with what velocity relative to the ice the platform will recoil?
Options
- A5 ~m / sec
- B10 ~m / sec
- C15 ~m / sec
- D20 ~m / sec
Correct answer
B. 10 ~m / sec
Step-by-step solution
Consider the situation shown in figure.Suppose the man moves at a speed w towards right and the the platform recoils at a speed ( V ) towards left, both relative to the ice. Hence, the speed of the man relative to the platform is ( V + w ). By the question, ( V + w = v ), or ( w = v - V ) (i) Taking the platform and the man to be the system, there is no external horizontal force on the system. The linear momentum of the system remains constant. Initially both the man and the platform were at rest. Thus, (0= MV - m