Question 613886: Please help with this vertical/projectile motion question:
Find the time it takes for a rocket launched from a 35-foot-high platform with an initial velocity of 30 feet/sec. to reach the ground.
Using many different methods, I came up with 2.7 seconds. Is this right, and if not, can you show me the right way of doing it and getting the right answer?
Thanks for your time!
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Find the time it takes for a rocket launched from a 35-foot-high platform with an initial velocity of 30 feet/sec. to reach the ground.
Using many different methods, I came up with 2.7 seconds
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h(t) = -16t^2+30t+35
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H(t) is zero when the rocket reaches the ground.
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Solve:
-16t^2 + 30t + 35 = 0
I graphed it and found a positive solution at t = 2.7.
You are correct.
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You could use the quadratic formula and find the same positive answer.
Cheers,
Stan H.
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