****TOO LONG BIO****

Question

A ball is dropped from the top of a 1,250-foot-tall building. The function f(x)=-16x^2+1,250 models the height, in feet, of the ball x seconds after it was dropped. During which interval is the height of the ball between 500 and 550 feet from where it was dropped?

 

A. 5.59-5.85 SECONDS

B.5.86-6.61 SECONDS

C.6.62-6.85 SECONDS

D. 6.86-8.84 SECONDS

Answer 1

We need to solve for x in f(x)=500 and 550.

-16x²+1250=500, 16x²=750, x²=750/16=46.875, x=6.85 secs approx

-16x²+1250=550, 16x²=700, x²=700/16=43.75, x=6.61 secs approx.

So answer C.