Question

In the given figure, the position - time graph of a particle of mass $0.1\text{kg}$ is shown. The magnitude of impulse at $t=2$ sec is:

• A. $0.2\text{kg -m/sec}$
• B. $-0.2\text{kg -m/sec}$
• C. $0.1\text{kg -m/sec}$
• D. $-0.4\text{kg -m/sec}$

Answer 1

The correct option is A $0.2\text{kg -m/sec}$

We know that slope of position-time graph gives the velocity of particle.
$\therefore$Velocity of particle at $t<2\text{sec}$
$u=\frac{4}{2}\text{m/s}$.

simillarly,
Velocity of particle at $t>2\text{sec}$
$V=0\text{m/s}$.

Also,
|Imulse$\left(J\right)$|=|Change in momentum|
|J|=$\Delta P$=|$m(v-u)$|
$=\left|0.1(0-\frac{4}{2})\right|$
$=0.2\text{kg -m/sec}$