A ball is thrown vertically upward from the top of a 100-foot tower, with an initial velocity of 20 ft/sec. Its position function is s(t) = -16t^2 + 20t + 100. What is its velocity in ft/sec when t = 1 second?

80 ft/s

Step-by-step explanation:

Given that,

A ball is thrown vertically upward from the top of a 96-ft tower, with an initial velocity of 16 ft/sec. Its position function is given by :

...(1)

When it hits the ground, s(t) = 0

At t = 3 s it will hit the fround.

We need to find its velocity when it hits the ground.

Differentiate equation (1) to find its velocity.

...(2)

Put t = 3 in equation (2)

Hence, when it will ground its velocity is 80 ft/s.