Answer 20 I just did that question
Answer: 4 seconds
Step-by-step explanation:
Given: The function
can be used to model the height of the ball where t is the time in seconds after the ball kicked and h(t) is the height in feet.
Differentiate the given function with respect to t , we get

Put h'(t)=0

Also, 
By second derivative test, h(t) is maximum at t=4.
Hence, the time in Devon which the ball reaches it maximum height = 4 seconds
Radius = 4 feet
Height = 3 feet
Formula :
Volume =
πr2h
———
3
Solution :
3.14 x 42 x 3
——————— =
3
3.14 x 16 x 3
——————— =
3
150.7964
—————-
3
Volume = 50.2655 feet³