What is its speed (in m/s)?

Question

A loaded gun is dropped on a frozen lake. The gun fires, with the bullet going horizontally in one direction and the gun sliding on the ice in the other direction. The bullet's mass is 0.04 kg, and its speed is 275 m/s. If the gun's mass is 1.8 kg, what is its speed (in m/s)?

Answer 1

Use the law of conservation of momentum: m₁v₁ = m₂v₂

m₁ = mass of the bullet (0.04 kg)

m₂ = mass of the gun (1.8 kg)

v₁ = velocity of the bullet (275 m/s)

v₂ = velocity of the gun (?? m/s)

(0.04 kg)*(275 m/s) = (1.8 kg)*(v₂)

v₂ = (0.04 kg)(275 m/s) ÷ (1.8 kg) = 6.1 m/s

The gun's velocity is around 6.1 m/s.