The diagram depicts a ‘ballistic pendulum’. A pellet of mass $m$ moving with speed $u$ strikes a block of mass $M$ that is initially at rest. The pellet becomes lodged in the block and makes the block move with speed $v$ immediately after the collision. If a pellet of mass $2m$, moving with speed $2u$, strikes a block of mass $2M$, what is the speed of the block immediately after the collision? (Ignore the slight increase in the mass of the block as the pellet’s mass is added during the collision.)
- A$v$
- B$v\sqrt{2}$
- C$2v$
- D$4v$