A bullet of mass 0.1 kg is fired on a wooden block to pierce through it,
Question:

A bullet of mass $0.1 \mathrm{~kg}$ is fired on a wooden block to pierce through it, but it stops after moving a distance of $50 \mathrm{~cm}$ into it. If the velocity of bullet before hitting the wood is $10 \mathrm{~m} / \mathrm{s}$ and it slows down with uniform deceleration, then the magnitude of effective retarding force on the bullet is ‘x’ N. The value

of ‘ $x$ ‘ to the nearest integer is______

Solution:

(10)

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

$0=(10)^{2}+2(-\mathrm{a})\left(\frac{1}{2}\right)$

$\mathrm{a}=100 \mathrm{~m} / \mathrm{s}^{2}$

$\mathrm{~F}=\mathrm{ma}=(0.1)(100)=10 \mathrm{~N}$