Question

A bullet of mass $50g$ is moving with a velocity of $500m{s}^{-1}$. It penetrates $10cm$ into a still target and comes to rest. Calculate the loss in kinetic energy of the bullet.

• A. $0J$
• B. $2500J$
• C. $5000J$
• D. $6250J$

Answer 1

Answer: (D)

$6250J$

Kinetic Energy, $K.E=0.5\ast m\ast v^2$

Given, m = 50 gram = 50/1000 = 1/20 Kg and Final velocity = 0 m/sec; initial velocity= 500 m/sec

Loss in $K.E=\frac{1}{2\times 20}(500\ast 500-0\ast 0)Joule$

Loss in $K.E=6250J$

Hence there is a decrease in kinetic energy of $6250J$.