Question

The muzzle velocity of a 50.0 g shell leaving a 3.00 kg rifle is 400 m/s. What is the recoil velocity of the rifle?​

Answer 1

Explanation:

6.67 m/s is your right answer

Answer 2

m₁v₁ + m₂v₂ (before collision) = m₁v₁ + m₂v₂ (after collision)

Here,

The bullet and the gun are of one mass before the collision, and are sitting still, which cancels out the first half of the equation.

⇒ m₁v₁ = -m₂v₂

⇒ 0.05 × 400 = -3 ×  V₂

⇒ 20 = -3 × V₂

⇒ V₂ = 20/-3

⇒ V₂ = -6.67 m/s

$\boxed{\bold{Recoil \:Velocity \:of \:the \:rifle=-6.67\:m/s}}$