Question

A 10kg bullet moving at 200m/s stops after penetrating 5cm of wooden plank. The average force ecerted on the bullet will be

Answer 1

Given :
mass=10g=10/1000=0.01kg
Initial speed=u=200m/s
final velocity= o m/s
S=5cm=5/100=0.05m

From third equation of motion :V²-u²=2as

0²-(200)²=2ax0.05

-40000=ax5x2/100

-40000=a/10

a=-400000m/s²

From Newton's Second law:
F=ma
=0.01x(-400000)
=-4000N

∴ A force of 4000N acts in opposite direction.

Answer 2

Answer 4000N

Explanation:

using v² = u²- 2as putting final

velocity v=0 and s =0.05m

4000/(2×0.05)=400000m/s²

Average force= mass×acceleration

=.001×400000 = 4000n

Hope it helps you