A Ping-Pong ball is given an upward initial velocity. The force of air resistance causes the times of ascent and descent to be unequal. Which time is greater?

Time of ascent is greater than time of descent.

Explanation:

The gravitational force always acts in the downward direction. The air drag always opposes the motion.

During ascent, the gravitational force and air drag act in opposite direction to the motion where as during descent, only air drag acts in opposite direction to the motion of the ball while gravitational force acts in the same direction. Thus, the time of ascent and descent become unequal with time of ascent being greater than time of descent.