## College Physics (4th Edition)

The correct answer is: (e) $0~s, 4~s, 8~s$
When an object is in SHM, the acceleration has its maximum magnitude when the speed is zero. From the graph of $v_x$ versus $t$, we can see that when the speed is zero, the slope of the the graph, which is the acceleration, has a maximum magnitude. The acceleration has its maximum magnitude at $t = 0~s, 4~s, 8~s$ The correct answer is: (e) $0~s, 4~s, 8~s$