The height of an object dropped from the top of a 64-foot building is given by h (t) = -16t^2+64. How long will it take the object to hit the ground?

1.86 s

Explanation:

Given the expression

h (t) = - 16t² + 64 ... Equation 1

Where h = height of the object, t = time it will take the object to hit the ground.

Given: h = 64 foot.

We have to concert from foot to meters

If 1 foot = 0.3048 meters

Then, 64 foot = 0.3048*64 = 19.51 meters.

We substitute the value of h into equation

119.51 = - 16t²+64

-16t² = 199.51-64

-16t² = 55.51

t² = 55.51/-16

t² = 3.469

t = √3.469

t = 1.86 s.

Hence it will take the object 1.86 s to hit the ground.