First slide

Motion of centre of mass

Question

A body initially at rest, breaks up into two pieces of masses 2 M and 3 M respectively, together having a total kinetic energy E. The piece of mass 2 M, after breaking up, has a kinetic energy :

Moderate

A

$\frac{E}{2}$
B

$\frac{E}{5}$
C

$\frac{3 E}{5}$
D

$\frac{2 E}{5}$

Solution

According Conservation of Linear Momentum
$\begin{array}{l} 0 = 2 M V_{1} - 3 M V_{2} - - - - (1) \\ E = \frac{1}{2} 2 M V_{1}^{2} + \frac{1}{2} 3 M V_{2}^{2} \\ = K_{1} + \frac{1}{2} 3 M V_{2}^{2} - - - - - (2) \\ (1) \Rightarrow V_{2} = \frac{2 V_{1}}{3} - - - - - (3) \end{array}$
(3) in (2) and solve we get
$K_{1} = \frac{3 E}{5}$

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