Question

A 90gm ball moving at 100 cm/s collide head on with a stationary 10 gm ball. The coefficient of restitution is 0.5 . The loss of K.E. is

• A. 45,000 erg
• B. 22,500 erg
• C. 33,750 erg
• D. 0 erg

Answer 1

The correct option is C 33,750 erg

For any collision, loss in energy is,

$LossofK.E.=\frac{1}{2}\times \frac{m_1{m}_2}{(m_1+m_2)}\times (u_1-u_2{)}^2\times (1-e^2)$

But $m_1=90$gm$,m_2=10$gm$,u_1=100$cm${}^{-1},u_2=0,e=0.5$

$\Rightarrow LossofK.E=\frac{1}{2}\times \frac{900}{100}\times {100}^2\times (1-{0.5}^2)=33750$ ergs

The problem is in CGS therefore unit of work is erg.