A block of mass 'm' is connected to another block of mass 'M' by a spring (massless) of spring constant 'k' The blocks are kept on a smooth horizontal plane. Initially the blocks are at rest and the spring is unstretched Then a constant force 'F' starts acting on the block of mass 'M' to pull it. Find the force on the block of mass 'm' :

Options

A. `(MF)/((m+M))`
B. `(mF)/(M)`
C. `((M+m)F)/m`
D. `(mF)/((m+M))`

Answer

D

Explanation

The acceleration of the system is:
`a=F//(M+m)`
The force acting on mass m is:
`F'=ma=(mF)/((M+m))`