Question

A person with mass 65 kg, standing still, throws an object at 4 m/s. If the
recoil velocity of the person is 3.5 m/s, what is the mass of the object?
Assume the surface to be frictionless.

Answer 1

Explanation:

Momentum before = momentum after

m₁ u₁ + m₂ u₂ = m₁ v₁ + m₂ v₂

(65 kg) (0 m/s) + m (0 m/s) = (65 kg) (-3.5 m/s) + m (4 m/s)

m ≈ 57 kg