Question

A bullet of mass 0.1 kg, moving with a speed of 200 ms-1 penetrates through a distance of 0.1 m in a block of wood. Calculate, in kilogram force, the resistance offered by the block.​

Answer 1

Given:

A bullet of mass 0.1 kg, moving with a speed of 200 ms-1 penetrates through a distance of 0.1 m in a block of wood.

To find:

Resistance offered by block?

Calculation:

First of all, let's find out the acceleration of bullet:

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

$\implies \: {0}^{2} = {(200)}^{2} + 2a(0.1)$

$\implies \: 0.2a = - 200 \times 200$

$\implies \: a = - 1000\times 200$

$\implies \: a = - 200000 \: m {s}^{ - 2}$

Now, force experienced is :

$F = m \times a$

$\implies \: F = 0.1 \times ( - 200000)$

$\implies \: F = - 20000 \: N$

$\implies \: F = - 20 \:k N$

So, resistance experienced is 20 kN.