Question

A 20 gm bullet moving at 300 m/s stops after penetrating 3 cm of bone. Calculate the average force exerted by the bullet.

Answer 1

Heres what I have done:

Answer in attachment.

Answer 2

Initial velocity = Vo = 300 m/s
Final velocity = V = 0 m/s
Distance travelled in bone = d = 3 cm = 0.03 m

Using
${v}^{2} = {vo}^{2} + 2ad$

$0 = {(300)}^{2} + 2a(0.03)$

$2a(0.03) = - 90000$

$a = -1500000 \: \frac{m}{ {s}^{2} }$

Force = m a

force exerted by bullet will be,

$= ma$

$= \frac{20}{1000} (1500000)$

$= 30,000 \:$N