Answer
10 m/s decrease each second while rising straight up.
10 m/s increase each second while dropping straight down.
The times are the same.
Work Step by Step
This is discussed on pages 46-47.
Whether it is rising or falling, the acceleration of a freely falling object, in the absence of air resistance, is always $10 \frac{m}{s^{2}}$ directed downward.
Each second while going straight up, the baseball's speed decreases by 10 m/s.
Each second while dropping straight down, the baseball's speed increases by 10 m/s.
With no air resistance, the time going up equals the time coming down.
