Question

A 500 gram bullet is fired at 550 m/s into a 3.5 kg wooden block at rest. The velocity of block afterward is 65 m/s. The bullet passes through the block and emerges with what velocity?​

Answer 1

Given:

A 500 gram bullet is fired at 550 m/s into a 3.5 kg wooden block at rest. The velocity of block afterward is 65 m/s.

To find:

Final Velocity of bullet ?

Calculation:

In these types of questions, it is best to apply CONSERVATION OF LINEAR MOMENTUM:

$\sf \therefore \: P1 = P2$

$\sf \implies \: m_{bt.}u_{bt.} + m_{box}u_{box} = m_{bt.}v_{bt.} + m_{box}v_{box}$

$\sf \implies \: (0.5 \times 550) + m_{box}(0) = (0.5)v_{bt.} + (3.5 \times 65)$

$\sf \implies \: 275 = (0.5)v_{bt.} +227.5$

$\sf \implies \: (0.5)v_{bt.} = 275 - 227.5$

$\sf \implies \: (0.5)v_{bt.} =47.5$

$\sf \implies \: v_{bt.} =95 \: m {s}^{ - 1}$

So, final velocity of bullet is 95 m/s.