Answer to Question #227216 in Physics for Praiz

Question

A bullet of mass 40kg is fired horizontally in to a wooden block with a speed of 10m/s the bullet is brought to rest in the block in 0.2s by constant resistance.
Calculate.
* Magnitude of the resistance.
*Distance moved by the bullet.

Answer 1

Given:

$m=40\:\rm kg$

$v_i=10\:{\rm m/s}, \quad v_f=0\:\rm m/s$

$t=0.2\:\rm s$

(a) Magnitude of the resistance

$$F=m\frac{\Delta v}{\Delta t}=40*\frac{10}{0.2}=4000\:\rm N$$

(b) Distance moved by the bullet

$$d=\frac{v_f+v_i}{2}t=\frac{10}{2}*0.2=1\:\rm m$$