Question

A bullet of mass 100g moving with 20 m/s strikes a wooden plank and penetrates upto 20cm . Calculate the resistance offered by wooden plank

• A. ${10}^{2}N$
• B. ${10}^{3}N$
• C. ${10}^{4}N$
• D. ${10}^{5}N$

Answer 1

The correct option is A ${10}^{2}N$

Given,

Mass of bullet$=100g={10}^{-1}m$

Velocity of bullet $V=20\frac{m}{s}$

Distance travelled inside wood $x=20cm=\frac{1}{5}m$

Now , work done in stopping the bullet =kinetic energy of bullet

$F\times x=\frac{1}{2}m{v}^2$

$F=\frac{1}{2\times 0.2}\times {10}^{-1}\times {20}^2$

$F={10}^2$N