Question

Dan uses a remote control to make his drone take off from the ground. Function h represents the height, in feet, of the drone t seconds after it begins flying.

Which statement correctly describes this situation?

A.
The drone is on the ground at 0 and 16 seconds.
B.
The drone is on the ground at 0 and 4 seconds.
C.
The drone is on the ground at 2 and 4 seconds.
D.
The drone is on the ground at 0 and 2 seconds.

Answer 1

Hi,

The drone is on the ground at 0 and 4 seconds.

XD

Answer 2

Answer: C. The drone is on the ground at 0 and 4 seconds.

Explanation:

Here the function that shows the height of the drone,

h(t) = -16(t-2)^2+64

Where t is the time in seconds.

Since, the drone is ground when, h(t) = 0

-16(t-2)^2+64=0

-16(t-2)^2 = -64 (by subtracting 64 from both sides 64)

(t-2)^2 = 4 (dividing both sides by -16 )

t^2-4t+4= 4

t^2-4t= 0 (by subtracting 4 from both sides)

t(t-4)= 0

⇒ t = 0 or t = 4

Thus, Option C is correct.