Question 1: Laws of Motion

Question

A gun applied a force $F$ on a bullet which is given by $$F=\left(100-0.5 	imes 10^5 tight) \mathrm{N}$$. The bullet emerges out with speed $$400 \mathrm{~m} / \mathrm{s}$$. Then find out the impulse exerted till force on the bullet becomes zero.

Accepted Answer

Given, Force applied by gun,
$$F=\left(100-0.5 	imes 10^5 tight) \mathrm{N}$$
Speed of bullet, $$v=400 \mathrm{~m} / \mathrm{s}$$
when $$\quad F=0$$
$$\Rightarrow \quad 100-0.5 	imes 10^5 t=0 \Rightarrow t=2 	imes 10^{-3} \mathrm{~s}$$
$$	herefore 	ext { Impulse, } I=\int F d t$$
$$\begin{aligned}
& =\int_\limits0^{2 	imes 10^{-3}}\left(100-0.5 	imes 10^5 tight) d t=\left[100 t-0.5 	imes 10^5 \frac{t^2}{2}ight]_0^{2 	imes 10^{-3}} \
& =100 	imes 2 	imes 10^{-3}-\frac{0.5 	imes 10^5}{2} 	imes 4 	imes 10^{-6}-0 \
& =0.2-0.1=0.1 \mathrm{~Ns}
\end{aligned}$$

Answer

0.2 Ns

Answer

0.3 Ns

Answer

0.1 Ns

Answer

0.4 Ns

Laws of Motion

A gun applied a force F on a bullet which is given by $F=\left(100-0.5 \times 10^5 t\right) \mathrm{N}. The bullet emerges out with speed 400 \mathrm{~m} / \mathrm{s}$. Then find out the impulse exerted till force on the bullet becomes zero.

Choose the correct answer: