Question

A bullet of mass $50g$ travelling at $500m/s$ penetrates $100cm$ into a wooden block. Find the average force exerted on the block.

• A. $0.625\times {10}^{4}N$
• B. $62.5\times {10}^{4}N$
• C. $6.25\times {10}^{4}N$
• D. $2.65\times {10}^{4}N$

Answer 1

The correct option is A $0.625\times {10}^{4}N$

Mass, $m=0.05kg$
Initial velocity, $u=500m/s$
Distance covered, $S=100cm=1m$

Final velocity $v=0$

Now, from the equation of motion

$v^2-u^2=2as$

$0-{\left(500\right)}^2=2\times a\times 1$

$a=-125000m/s^2$

Now, the average force exerted on the block

$F=ma$

$F=0.05\times 125000$

$F=6.25\times {10}^3$

$F=0.625\times {10}^{4}N$

Hence, the average force is $0.625\times {10}^{4}N$