Question

A 50 g bullet moving with velocity 10 m/s strikes a block of mass 950 g at rest and gets embedded in it. The loss in kinetic energy will be

• A. $100$%
• B. $95$%
• C. $5$%
• D. $50$%

Answer 1

The correct option is B $95$%

By conservation of momentum

final velocity of embeded body $=$ mass of bullet $\times$ velocity of bullet $÷$ mass of bullet $+$ mass of stationary body

Initial kinetic energy $=\frac{1}{2}\times 50\times 10\times 10=2500J$

final kinetic energy is $\frac{1}{2}\times 950\times V^2=\frac{1}{2}\times 950\times 100=47500J$

The loss is $K.E=$ final $K.E$ $-$ Initial $K.E$

$\frac{2500}{4}=100$%