A small block B is placed on another block A of mass 5 kg and length 20 cm. Initially, the block B is near the right end of block A. A constant horizontal force of 10 N is applied to the block A. All the surfaces are assumed frictionless. Find the time elapsed before the block B separates from A.

Explanation

Let the block m, towrds left through displacement x
` :. F_1 = k.x (compressed)`
` F_2 = k_2 x(expanded)`
Since they are in same directiion
`:. Resultant F= F_1+F_2=k_1x+k_2x`
`=x(k_1 +k_2)`
So, acceleration
`a=F/m (x(k_1+k_2))/m`.