Answer
The correct answer is:
(j) $3~s, 7~s$
Work Step by Step
When an object is in SHM, the object reaches maximum speed at the equilibrium point. The object then moves away from the equilibrium point until the speed is zero at a point of maximum amplitude.
The object is moving away from the equilibrium point in the intervals $2 \lt t \lt 4$ and $6 \lt t \lt 8$
The correct answer is:
(j) $3~s, 7~s$
