Question

An object is dropped from a small plane. As the object falls, its distance, d, above the ground after t seconds, is given by the formula d = –16t2 + 1,000. Which inequality can be used to find the interval of time taken by the object to reach the height greater than 300 feet above the ground?

Answer 1

The height here should be greater than 300 ft above the ground.

So d>300

The inequality will be:

-16t²+1000>300

-16t²+1000>300

-16t²>300-1000

-16t²>-700

-t²>-700/16

-t²>-43.75

t²<43.75

t<√43.75

t<6.61  or  (0 ,  6.61)

The Answer is 16t²+1000>300

and the interval of time will be (0 , 6.61) seconds