Answer:
t = 0.75 seconds
Step-by-step explanation:
Given that,
The initial speed of a ball, u = 7.5 m/s
We need to find the time taken by the ball to reach the maximum height. Let t is the time taken.
At maximum height, its final speed, v = 0 and it will move under the action of gravity.
Using the equation of motion to find t.

Use a = -g

Hence, the ball will take 0.75 seconds to reach the maximum height.