Question: A wooden block of mass 𝑀 rests on a horizontal surface. A bullet of mass 𝑚 moving in the horizontal direction strikes and gets embedded in it. The combined system covers a distance 𝑥 on the surface. If the coefficient of friction between wood and the surface is 𝜇, the speed of the bullet at the time of striking the block is (where 𝑚 is mass of the bullet)
(A) \sqrt{\dfrac{2Mg}{\mu m}}
(B) \sqrt{\dfrac{2\mu mg}{Mx}}
(C) \sqrt{2\mu gx}\left( \dfrac{M+m}{m}\right)
(D) \sqrt{\dfrac{2\mu mx}{M+m}}
Answer: Option (C)
Solution:
