Question

URGENT!!

A golf ball is hit with an initial velocity of 80 feet per second. H= -16t^2 + 80t.
1) When will the ball reach 48ft?
2) When will the ball reach 110ft?

Answer 1

9514 1404 393

Answer:

1. t = 0.697 seconds
2. never (the maximum height is 100 ft)

Explanation:

A graphing calculator provides a nice solution to this question.

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1) Put 48 ft in for H and solve for t:

48 = -16t^2 +80t

-3 = t^2 -5t

3.25 = t^2 -5t +6.25 = (t -2.5)^2

t = 2.5 ±√3.25

The ball will first reach 48 feet at t = 2.5 -√3.25 ≈ 0.697224 seconds.

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2) The equation tells us the maximum height occurs at t=2.5 seconds. That height is ...

H = -16(2.5^2) +80(2.5) = 100

The maximum height is 100 feet. The ball will never reach 110 feet.