Question

Regarding linear momentum of a body
a. It is a measure of quantity of motion contained by the body
b. Change in momentum is the measure of impulse
c. Impulse and acceleration act in opposite direction to the change in momentum
d. In the case of uniform circular motion the linear momentum is conserved.

• A. a & b are true
• B. b & c are true
• C. c & d are true
• D. a, b & c are ture

Answer 1

Answer: (A)

a & b are true

Linear momentum ($\overrightarrow{P}$) of a body of mass m and velocity $\overrightarrow{v}$ is expressed as:
$\overrightarrow{P}=m\times \overrightarrow{v}$.

SO the linear momentum is the measure of the quantity of motion contained by the body.

And impulse of a force is the change in momentum occurring due to the force.
So, Impulse acts in the same direction to the change in momentum.
Acceleration, $\overrightarrow{a}=\frac{\overrightarrow{F}}{m}=\frac{1}{m}\frac{d\overrightarrow{P}}{dt}$. So, acceleration also acts in the same direction as impulse.
Uniform circular motion corresponds to zero angular acceleration leading to constant angular momentum. Linear momentum, in this case, is not conserved when an external force is present.