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Suppose h(t) = -0.2t2 + 2t models the height, in feet, of a ball that is kicked into the air where t is
given as time, in seconds.
After how many seconds does the ball reach its maximum?

Answer 1

Explanation:

the point of extreme value we get a the zero dilution of the first derivative of the function.

h(t) = -0.2t² + 2t

h'(t) = -0.4t + 2

so,

-0.4t + 2 = 0

2 = 0.4t

t = 2/0.4 = 5 seconds

so, after 5 seconds the ball reaches its maximum height.

FYI : that height is then h(5).

-0.2×5² + 2×5 = -5 + 10 = 5 ft

so, all in all, a very weak kick in very low gravity ...