Question

A bullet of mass $20g$ travelling horizontally with a velocity of $100m/s$ strikes a wooden block and comes to rest in $0.05s$. Calculate the magnitude of force N exerted by the wooden block on the bullet.

Answer 1

Step 1: Given

Mass of the bullet, $m=20g=0.02Kg$

Initial velocity of the bullet, $u=100m/s$

Final velocity of the bullet, $v=0m/s$

Time, $t=0.05s$

Step 2: Calculate the acceleration

Using an equation of motion,

$$\begin{gathered} v=u+at \\ 0=100+a(0.05) \\ a=-2000m/s^2 \end{gathered}$$

Step 3: Determine the force acting on the bullet

Force F is given by,

$$\begin{gathered} F=ma \\ =0.02(-2000) \\ =-40N \end{gathered}$$

The value is -ve as the wooden block exerts the force opposite to the motion of the bullet

Therefore, the magnitude of the force exerted by the wooden block on the bullet is $40N$