Given, Weight of bullet (mB)=10gm =10×10−3kg Weight of block (M)=10kg Initial velocity of bullet (vi)=1000m∕s Final velocity of bullet (vf)=400m∕s By the law of conservation of momentum, mBvi=mBvf+10v [where, v= velocity of block ] (10×10−3)(1000)=(10×10−3)(400)+10v 10=4+10v 10v=10−4 v=