Question

A ball is thrown upward from the top of a building. The function below shows the height of the ball in relation to sea level, ft, in feet, at different times t in seconds:

f(t) = -16t^2 + 32t + 90

The average rate of change of f(t) from t = 4 seconds to t = 6 seconds is how many feet per second?

Answer 1

@math&ing001

Answer 2

It's impossible to tag him :P

Answer 3

Plug 4 for t and solve

Answer 4

I plugged 4 in for t and then 6 in for t because I know that's what you have to do but after that how do I solve?

Answer 5

Can you tell me what you get when t = 4 and t = 6?

Answer 6

I got:

f(4) = -16(4)^2 + 32(4) + 90
f(4) = -256 + 128 + 90
f(4) = 14

f(6) = -16(6)^2 + 32(6) + 90
f(6) = -512 + 192 + 90
f(6) = -230

Answer 7

@Mehek14

Answer 8

I got 4, -38 :\

6, -294

Answer 9

hmm how did you do the problems then?

Answer 10

f(t) = -16*4^2 + 32 * 4 + 90

-16 * 16 + 128 + 90

-256 + 128 + 90

-38

Answer 11

f(t) = -16*6^2 + 32*6 + 90

-576 + 192 + 90

-294

Answer 12

I see what I did wrong

Answer 13

So after that what am I supposed to do?

Answer 14

Slope formula

\(\bf{\dfrac{y_2-y_1}{x_2-x_1}}\)

Answer 15

So plug in the values

\(\bf{\dfrac{-294 - (-38)}{6-4}}\)

Answer 16

I got:

-256/2
-128

Answer 17

So -128 is the answer

Answer 18

but is it actually the answer because the ball can go -128 ft.

Answer 19

Yes because it is dropped from a building

Answer 20

oh ok I understand. Thanks so much!!! Can you help me with another problem?

Answer 21

Sure

Answer 22

do you want me to close this one first or can I just ask it here?

Answer 23

your choice

Answer 24

I closed it and I tagged you in the other problem