Question

A metal ball of mass $2kg$ moving with a velocity of $36km/h$ has an head-on collision with a stationary ball of mass $3kg$. If after the collision, the two balls move together, the loss in kinetic energy due to collision is

• A. $40J$
• B. $60J$
• C. $100J$
• D. $140J$

Answer 1

Answer: (B)

$60J$

Answer 2

Loss in kinetic energy

$\Delta K = \frac{1}{2}\frac{m_{1}m_{2}}{m_{1} + m_{2}}(u_{1} - u_{2})^{2} = \frac{1}{2}\frac{2 \times 3}{2 + 3}(10 - 0)^{2} = 60J.$