First slide

The steps in collision

Question

A 2 kg wooden block is suspended from fixed point by a light string of length 1 m. A body of mass 0.5 kg moving horizontally with velocity ‘V' strikes the block and sticks to it. After the impact the composite body swings in a vertical circle and comes to rest momentarily when the string is horizontal then V =

Moderate

A

20 m/s
B

$10 \sqrt{2} m / s$
C

$10 \sqrt{5} m / s$
D

$5 \sqrt{5} m / s$

Solution

It $V^{1}$ be the velocity of the block just after impact, then conserving linear momentum,
$0.5 \times V = (2 + 0.5) V^{1} \Rightarrow V^{1} = \frac{V}{5} m / s$
conserving energy, $\frac{1}{2} \times 2.5 \times {(V^{1})}^{2} = 2.5 \times 10 \times 1$
$\Rightarrow V^{1} = \sqrt{20} m / s$
$∴ \frac{V}{5} = \sqrt{20} \Rightarrow V = 10 \sqrt{5} m / s$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App