Confused with question

Question

 

Genevieve is going to throw a rock from the top of a trail overlooking the ocean. When she throws the rock upward from 160 feet above the ocean, the function h(t)=-16t^2 +48t +160 models the h, and the rock above the ocean as function of time t. Find 

a. The zeroes of this function that tells us when the rock will hit the ocean. 

B. When the rock will be 160 feet above the ocean. 

C. The height of the rock at t=1.5 seconds 

H()=0 , h() and h()=160 ft, (1.5)= ()

find the andswer

Answer 1

The first 3 parts are straight forward:

Part 1: set h(t) = 0 and solve the quadratic for t. Make sure you pick the correct root.

Part 2: set h(t) =160 and again solve the quadratic and pick the correct root.

Part 3: compute h(1.5)

What is wanted in Part 4 is not clear. I suspect you will want the maximum height which will be found at h(t_m) where t_m is the time when the derivative of h = 0.