Question

Find out the correct statement from the options given below:

• A. Impulse is a scalar quantity
• B. Dimensions of impulse are $\left[{\text{ML T}}^{-2}\right]$
• C. Impulse is a property of particles.
• D. Gravitational force is always non-impulsive.

Answer 1

The correct option is D Gravitational force is always non-impulsive.

Impulse is a vector quantity having direction along the change in momentum.
$\overrightarrow{F}=\frac{\overrightarrow{dP}}{dt}$
$\therefore \overrightarrow{J}=\overrightarrow{F}dt=\overrightarrow{dP}$
where $\overrightarrow{J}$ is the impulse.
$\Rightarrow$ Impulse is a vector quantity and unit of impulse is ${\text{kg.ms}}^{-1}$
Hence, ${\text{MLT}}^{-1}$ are the dimensions of impulse. Option (a) and (b) are wrong.

Impulse is associated with change in momentum of a particle, when force acts for very short interval. It is not a property of particles. Option (c) is wrong.

Gravitational force does not act on a body suddenly for a short interval of time, hence it is a non-impulsive force. Option (d) is correct.