Question

An object drops from 144 ft, the function h(t) = -16x^2 + 144 gives the height of the object after t seconds. When will the object hit the ground?

Answer 1

The height of the object that drops from 144 feet was given by the function     
     h(t) = -16t^2 + 144 

We now set this equation equal to zero because the height of the ground is zero:
     0 = -16t^2 + 144 
     16t^2 = 144 
     t^2 = 144/16 

Taking the square root of both sides, we get the time t the object will hit the ground:
     t^2 = 9
     t = 3 seconds
Therefore, the answer is 3 seconds.