Question

A bullet of mass $0.4g$ moving with a speed of $600m/s$ penetrates a heavy wooden block. It stops after a penetration of $50cm$. The resistive force exerted by the block on the bullet is

• A. $1440N$
• B. $1480$
• C. $270N$
• D. none

Answer 1

The correct option is D none

Given:

Mass=.4 g=.4/1000 kg

U=600m/s

S= 50cm=.5m

Apply third equation of motion to find out the resistive acceleration exerted by block on wood

$v^2=u^2+2as$

$0=360000+2a\times 0.5$

$a=-360000m/s^2$

Resistive force $=m\times a=360000\times \frac{0.4}{1000}=144N$