Question

A bullet travelling at 500 m/s is brought to rest by an impulse of 50 N*s. What is the mass of the bullet?

Answer 1

Impulse can be expressed as a change in momentum from one moment of time to another: $J = \Delta p = m v_2 - m v_1$.

The initial speed is $v_1 = 500 \frac{m}{s}$, and final is $v_2 = 0 \frac{m}{s}$, therefore the mass of the bullet is: $m = \frac{J}{v_2} = \frac{50 N \cdot s}{500 \frac{m}{s}} = 0.1 kg = 100 g$,