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If an object is dropped from a height of 144 feet, the function h(t)=-16t^2+144 gives the height of the object after t seconds. When will the object hit the ground
A. 3s
B. 6s
C. 1.5 s
D. 9s


Sagot :

Answer:

A. 3s

Step-by-step explanation:

The height of the object after t seconds is given by:

[tex]h(t) = -16t^2 + 144[/tex]

When will the object hit the ground?

It hits the ground after t seconds, and t is found when [tex]h(t) = 0[/tex]. So

[tex]h(t) = -16t^2 + 144[/tex]

[tex]0 = -16t^2 + 144[/tex]

[tex]16t^2 = 144[/tex]

[tex]t^2 = \frac{144}{16}[/tex]

[tex]t^2 = 9[/tex]

[tex]t = \sqrt{9}[/tex]

[tex]t = 3[/tex]

3 seconds, so the correct answer is given by option a.