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A ball is tossed into the air. the height of the ball as a function of time can be described by the equation h=-16t^2+72th=−16t
2
+72t, In this equation h is the height of the ball in feet and t is time in seconds.



After how many seconds will the ball hit the ground?

Respuesta :

Answer:

4.5 seconds

Step-by-step explanation:

Given

h = - 16t² + 72t

When the ball hits the ground, then h = 0 , equating to zero gives

- 16t² + 72t = 0 ( divide through by - 8 )

2t² - 9t = 0 ← in standard form

t(2t - 9) = 0 ← in factored form

Equate each factor to zero and solve for t

t = 0 ← time when ball is thrown

2t - 9 = 0 ⇒ 2t = 9 ⇒ t = [tex]\frac{9}{2}[/tex] = 4.5 ← time when ball hits ground

The ball hits the ground after 4.5 seconds