Question

A bullet of mass 18.8 grams is fired with a speed of 399 meters per second toward a wood block of mass 277 grams initially at rest on a very smooth surface. What is the change in momentum of the bullet if it ricochets in the opposite direction with a speed of 386 meters per second? The answer must be in 3 significant digits.

Answer 1

Given data

*The given mass of the bullet is m = 18.8 g = 0.0188 kg

*The bullet is moving at a speed is u = 399 m/s

*The given final speed of the bullet is v = -386 m/s

*The mass of the wooden block is M = 277 g = 0.277 kg

The formula for the change in momentum is given as

$\begin{gathered} \Delta p=mv_{}-mu \\ =m(v_{}-u_{}) \end{gathered}$

Substitute the known values in the above expression as

$\begin{gathered} \Delta p=0.0188(-386-399) \\ =-14.758\text{ kg.m/s} \end{gathered}$

Hence, the change in momentum is -14.758 kg.m/s