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5.Work, Energy, Power and Collision
medium
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
A
$\frac{E}{2}$
B
$\frac{E}{5}$
C
$\frac{{3E}}{5}$
D
$\frac{{2E}}{5}$
(NEET-2017)
Solution
From the law of conservation momentum, $p_{1}=p_{2}$
Kinetic energy, $E=\frac{p^{2}}{2 m}$
$E \propto \frac{1}{m}$
$\frac{E_{1}}{E_{2}}=\frac{m_{2}}{m_{1}}=\frac{3 M}{2 M}=\frac{3}{2}$
$\frac{E_{1}}{E_{1}+E_{2}}=\frac{3}{3+2}=\frac{3}{5}$
$\frac{E_{1}}{E}=\frac{3}{5}$
$E_{1}=\frac{3 E}{5}$
Standard 11
Physics
