Question

In the figure the position time graph of a particle of mass $0.1kg$ is shown. Find the impulse at $t=4sec$ :

• A. $0.2kgcm{s}^{-1}$
• B. $-0.2kgcm{s}^{-1}$
• C. $0.1kgcm{s}^{-1}$
• D. $-0.4kgcm{s}^{-1}$

Answer 1

The correct option is B $-0.2kgcm{s}^{-1}$

Just before 4 seconds, velocity of particle $=2cm/s$ (slope of graph).
Just after 4 seconds, velocity $=0$.
Thus change in velocity at 4 seconds $=-2cm/s$
Thus impulse $=m\Delta v$
or, Impulse$=0.1\times -2=-0.2kgcm/s$