shannoncorbett
contestada

If an object is dropped from a height of 85 feet, the function h(t)=-16t^2+85, gives the height of the object after t seconds approximately when will the object hit the ground

Respuesta :

Serpentiel
The object will hit the ground once the height equals to zero.

[tex]h(t)=-16t^2+85 \\0=-16t^2+85 \\16t^2=85 \\t^2=\frac{85}{16} \\t=\sqrt{\frac{85}{16}}=\pm\frac{\sqrt{85}}{4}[/tex]

The negative answer does not fit the condition of the problem [tex]\Rightarrow[/tex] the answer is [tex]\frac{\sqrt{85}}{4}\approx2.31 \ seconds[/tex].

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