When Mr. Smith kicks a football, it has a vertical speed of 20 m/s, and its height, h in meters after t seconds can be modeled by the equation h=20t−5t^2 .

Part A.
How long is the football in the air before it lands on the ground?
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seconds

Part B
In how many seconds will the football reach its maximum height?
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seconds
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​Part C
​What is the maximum height that the football will reach?
​
meters