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?

Answer 1

Jessica,

You asked -

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?

Answer: To solve this equation we know that the ground is at a height of zero. We then set h = 0 and solve for t. Using the equation given

0 = -16t^2 +64; now I am going to isolate the term with the variable t

16t^2 = 64; next divide each side by 16 to isolate just the variable

t^2 = 64/16; simplify

t^2 = 4; now take the square root of both sides

t = sqrt (4); this yields two answers

t = 2 or -2; since time doesn't move backwards we can eliminate the answer of -2 leaving us with

t=2 or it takes 2 seconds for the object to hit the ground.

Warm regards,

Ray