A bullet of mass 20 g is moving with a speed of 150 ms -1. It strikes a target and is brought to rest after piercing 10 cm into it. Calculate the average force of resistance offered by the target.

Question

A bullet of mass 20 g is moving with a speed of 150 ms -1. It strikes a target and is brought to rest after piercing 10 cm into it. Calculate the average force of resistance offered by the target. (A) 2500 N (B) 2000 J (C) 2250 N (D) 2100 J

Tardigrade Admin · Accepted Answer

Given, m=20 g =0.02 kg , u=150 ms -1, v=0 and s=10 cm =0.1 m According to the work-energy theorem, we have K-K prime=W=F s ∴ (1/2) m u2-0=F s ⇒ F=(m u2/2 s)=(0.02 ×(150)2/2 × 0.1) =2250 N

Q. A bullet of mass $20 g$ is moving with a speed of $150 m s^{- 1}$ . It strikes a target and is brought to rest after piercing $10 c m$ into it. Calculate the average force of resistance offered by the target.

2500 N

2000 J

2250 N

2100 J

Given, $m = 20 g = 0.02 k g, u = 150 m s^{- 1}, v = 0$
and $s = 10 c m = 0.1 m$
According to the work-energy theorem, we have
$K - K^{'} = W = F s$
$∴ \frac{1}{2} m u^{2} - 0 = F s$
$\Rightarrow F = \frac{m u ^{2}}{2 s} = \frac{0.02 \times ( 150 ) ^{2}}{2 \times 0.1}$
$= 2250 N$

Q. A bullet of mass 20g is moving with a speed of 150ms−1. It strikes a target and is brought to rest after piercing 10cm into it. Calculate the average force of resistance offered by the target.