Question

Fig shows the position-time (x-t) graph of one-dimensional motion of a body of mass $0.4\,kg$. What is the time interval between consecutive impulses received by body?

A. $2s$
B. $4s$
C. $8s$
D. $16s$

Answer 1

Hint: For the first positive slope it is receiving some impulses and for the next negative slope, it will decrease or lose some impulse. The figure shows that the incline of the (x-t) diagram changes from positive to negative at time two seconds, and it changes from negative at time = four seconds, etc. Hence the course of speed is gotten after at regular intervals. Henceforth the body must get continuous driving forces after like clockwork.

Complete answer:
The figure shows that the incline of the diagram changes from positive to negative at time two seconds, and it changes from negative at time = four seconds, etc. Hence the course of speed is gotten after at regular intervals. Henceforth the body must get continuous driving forces after like clockwork.

The direction of velocity is reversed after every two seconds. Hence, the body must be receiving consecutive impulses after every two second.For the first positive slope it is receiving some impulses and for the next negative slope, it will decrease or lose some impulse.In this way, the right alternative is option A two second.

Hence, option A is the correct answer.

Note: While solving the problem, most of the students tend to make mistakes while finding the duration of time in which the velocity is reversed. It is important to note that velocity is a vector quantity, it both has direction and magnitude. It is important to note that impulse is nothing but a physical quantity, which defines the net effect of a force which acts over a time duration. It is important to remember that this is an important concept while we study momentum.