passwella.
Menu

JAMB Physics 1984 Question 36

Question 36

Newton's Laws and Momentum

A gun of mass 2.0 kg fires a bullet of mass 1.6 × 10−2 kg due East. If the bullet leaves the nozzle of the gun with a velocity of 150 m s−1, what is the recoil velocity of the gun?

  1. A.150 m s−1 due West
  2. B.1.2 × 10−4 m s−1 due West
  3. C.1.2 m s−1 due West
  4. D.1.2 m s−1 due East
  5. E.150 m s−1 due East
Show the answer and explanation

Answer: C (1.2 m s−1 due West)

Explanation

Momentum is conserved: 2.0v = 1.6 × 10−2 × 150 = 2.4, so v = 1.2 m s−1, in the opposite direction (West).