Question

A man holding a rifle (mass of person and rifle together is 100 kg) stands on a smooth surface and fires 10 shots horizontally in 5 sec. Each bullet has a mass 10 g with a muzzle velocity of 800 m/s. The velocity which the rifle man attains after firing 10 shots will be:

• A. 8 m/s
• B. 0.8 m/s
• C. 0.08 m/s
• D. -0.8 m/s

Hint:

Conservation of momentum applies to the recoil of the rifle after firing each bullet.

Answer 1

The Correct Option is B

The momentum conservation law gives: \[ m_{\text{rifle}} v_{\text{rifle}} = m_{\text{bullet}} v_{\text{bullet}} \times n \] where \( m_{\text{rifle}} = 100 \, \text{kg} \), \( v_{\text{bullet}} = 800 \, \text{m/s} \), and \( n = 10 \) shots. Using these values, the final velocity of the rifleman is calculated to be \( 0.8 \, \text{m/s} \).
Final Answer: \[ \boxed{0.8 \, \text{m/s}} \]