Question

The acceleration-time graph of a particle moving along a straight line is as shown in figure. At what time the particle acquires its initial velocity?

• A. $12sec$.
• B. $5sec$.
• C. $8sec$.
• D. $16sec$.

Answer 1

The correct option is C $8sec$.

Area under the acceleration-time graph give the change in velocity of the object.

For particle to acquire its initial velocity again i.e. $\Delta v=0$

Area under the graph must be also be zero.

Since the graph is a straight line, the area under the graph for $0\le t\le 4$ will cancel out the area for $4\le t\le 8$. Thus after $8$ seconds, the particle will acquire its initial velocity.