Question

An object is dropped from a height of 144 feet off the ground. The height

h
of the object after
t
seconds can be found using the function
h
(
t
)
=
144
−
16
t
2


When will the height be 128 feet?
seconds

When will the object reach the ground?
seconds

Answer 1

The height will reach 128 feet after 1 second.

The object will reach the ground after 3 seconds.

Explanation:

Plug in the height into the equation: h(t)=144-16t^2

Solve for t.

Ex:

128=144-16t^2, subtract 144 on both sides

-16=-16t^2, divide -16 on both sides

1=t^2, find the square root of both sides

1=t