<PRE><B>Question 166564</B>
Part a:

h(t) = -16t^2 + 64
h(1) = -16(1^2) + 64 
h(1) = -16(1) + 64 
ANSWER: h(1) = 48 feet

Part b:

The time it takes for the ball to hit the earth is the time from x=0 to the x intercept. 

Since h is a function of time h(t), All you need to do is set h=0.

0 = 16t^2 + 64   Now subtract 64 on both sides.
-64 = -16t^2   Now divide both sides by -16.
4 = t^2   Now square root both sides.
2 = t

ANSWER: It takes 2 seconds for the ball to reach the ground.

Note: For you problem to make sense as a math problem, it MUST be -16t^2. This could be a copying error.

Kevin

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