SOLUTION: The function y=-5t^2+20t+2 gives the approximate height, h metres, of a thrown football as a function of time, t seconds since it was thrown. The ball hit the ground before a recei
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-> SOLUTION: The function y=-5t^2+20t+2 gives the approximate height, h metres, of a thrown football as a function of time, t seconds since it was thrown. The ball hit the ground before a recei
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Question 1132878: The function y=-5t^2+20t+2 gives the approximate height, h metres, of a thrown football as a function of time, t seconds since it was thrown. The ball hit the ground before a receiver get near it.
a) From what height was the football thrown?
b) How long was the ball in the air, to the nearest tenth of a second?
c) For how many seconds was the height of the ball less than 17m?
Thanks Answer by ikleyn(52780) (Show Source):
(a) Substitute t= 0 into the right side expression and calculate.
What you will get, is clear even without calculation.
It is the constant term value of 2 meters.
(b) Solve the quadratic equation -5t^2 + 20t + 2 = 0 and use its positive root as your answer.
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