Two blocks of mass 2 kg and 4 kg are kept in contact with each other on a smooth horizontal surface. A horizontal force of 12 N is applied on the first block due to which they move with certain constant acceleration. Calculate the force between the blocks.

Explanation

Let a = common acceleration of blocks,
R = Force between the two blocks
From FBD of block 1
`F-R=m_(1)a " "...(i)`
From FBD of block 2,
`R=m_(2)a " " ...(ii)`
`therefore ` From (i) & (ii), `F=(m_(1)+m_(2)).a`
`therefore a=(F)/(m_(1)+m_(2))=(12)/(6)=2m//sec^(2)`
`therefore ` Force between blocks `R=m_(2)a = (4 xx 2) N=8N`.