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The height, h, in feet of a golf ball above the ground after being hit into the air is given by the equation, h = -16t^2 + 64t, where t is the number of seconds elapsed since the ball was hit. How many seconds does it take for the golf ball to hit the ground?

User Jarek
by
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1 Answer

2 votes
The ball is on the ground whenever the height is 0:


-16t^2+64t=0\implies-16t(t-4)=0\implies t=0,t=4

Obviously,
t=0 is the time when the ball is thrown, so ignore that. It thus takes the ball
t=4 seconds to hit the ground after it's been launched.
User Nickolayratchev
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8.6k points
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