While working on a roof, Rob dropped his hammer. The hamer's fall can be represented by the equation h=-16t^2+20 (where t=time in seconds and h=height in feet) How long will it take the hammer to reach the ground?

Respuesta :

Answer:

It will take 1.12 seconds for the hammer to reach the ground.

Step-by-step explanation:

The height of the hammer after t seconds is given by the following equation:

[tex]h(t) = -16t^{2} + 20[/tex]

How long will it take the hammer to reach the ground?

This is t for which h(t) = 0. So

[tex]h(t) = -16t^{2} + 20[/tex]

[tex]-16t^{2} + 20 = 0[/tex]

[tex]16t^{2} = 20[/tex]

[tex]t^{2} = \frac{20}{16}[/tex]

[tex]t^{2} = \frac{1.25}[/tex]

[tex]t = \pm \sqrt{1.25}[/tex]

Time is a positive measure, so

[tex]t = 1.12[/tex]

It will take 1.12 seconds for the hammer to reach the ground.

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