# 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 of the block of mass  m. Option 1) Option 2) Option 3) Option 4)

As we learnt in

When 2 Blocks are in Contact -

$F-f=m_{1}a$

$f=m_{2}a$

- wherein

$a=\frac{F}{m_{1}+m_{2}}$

$f=\frac{m_{2}F}{m_{1}+m_{2}}$

$: Acceleration \: of\: the\: system\: a= \frac{F}{m+M}$

$Force \: on \: block\: of \: mass\: m= ma= \frac{mF}{m+M}$

Correct option is 4.

Option 1)

This is an incorrect option.

Option 2)

This is an incorrect option.

Option 3)

This is an incorrect option.

Option 4)

This is the correct option.

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