Chapter 5, Problem 3RQ

Why is it incorrect to say that impulse equals momentum?

To determine

The reason behind the statement, impulse equals momentum, being incorrect.

Answer to Problem 3RQ

The reason behind the statement, impulse equals momentum, being incorrect is that impulse is equal to the change in momentum.

Explanation of Solution

The term momentum can be understood as the quantity in motion. The change in momentum of a body can take place due to the variation in mass or velocity. When the velocity of a body varies, it gives rise to acceleration. Also, the acceleration is produced when force is exerted over a body.

The effect of force that is produced in a body, when acted for certain interval of time, is termed as impulse. The effect of force on an object leads to change in momentum. Thus, impulse is equal to change in momentum, and this can be represented by expression given below.

$\begin{array}{c}I=\Delta p\\ Ft=m\Delta v\end{array}$

Here,

$m$ is the mass

$t$ is the time

$F$ is the force

$\Delta v$ is the change in velocity.

Conclusion:

Therefore, the reason behind the statement, impulse equals momentum, being incorrect is that impulse is equal to the change in momentum.