5. If an object is dropped from a height of 400 feet, the function h(t) = -16t2 + 400 gives the height of the object after t seconds. When will the object hit the ground? (1point)
a. 25 seconds
b. 10 seconds
c. 5 seconds
d. 2.5 seconds

Question

5.	If an object is dropped from a height of 400 feet, the function                      h(t) = -16t2 + 400 gives the height of the object after t seconds. When will the object hit the ground? (1point)
a.	25 seconds
b.	10 seconds
c.	5 seconds
d.	2.5 seconds

anonymous · Answer

when h(t) = 0
it has hit ground

0 = -16t^2 +400
0 = t^2 - 25