Problema Solution

h=-3.9t^2 + 11.2t+40 how long after the ball was thrown did it hit the ground

t represents seconds after the ball was thrown

Answer provided by our tutors

when the ball hits the ground the height h = 0 thus we need to solve the quadratic equation


-3.9t^2 + 11.2t+40 = 0


and find the positive roots


t = 4.95 sec


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after 4.95 seconds the ball will hit the ground.