Two identical blocks each of mass `M=9kg` are placed on a rough horizontal surface of frictional coefficient `mu=0.1`. The two blocks are joined by a light spring and block B is in contact with a vertical fixed wall as shown in figure. A bullet of mass `m=1kg` and `v_0=10m//s` hits block A and gets embedded in it. Find the maximum compression of spring. (Spring constant `=240N//m, g=10m//s^2`)

Answer

A

Explanation

For the collision
`1xx10=10xxvimpliesv=1m//s`
If x be the maximum compression
`1/2xx10xx1^2=mu(m+M)gx+1/2kx^2`
`5=10x+120x^2`
`impliesx=1/6m`