Problem 2-52.
(a) Straight line in an x-t graph indicates constant velocity. The line segment between t=0 to t=17s appears to be straight, hence the object should travel with a constant velocity in this time period.

(b) The velocity is given by the slope of the x-t curve. The curve is steepest at t 28s. The objects travels the fastest at this time.

(c) Horizontal slope indicates zero velocity. The object is instantaneously at rest at t 37.5s.

(d) The object travels in both directions. It initially travels in the positive direction (increasing x). It turns around and travels backward (decreasing x) at t 37.5s.