Question

Suppose an object is thrown upward with an initial velocity of 52 feet per second from a height of 125 feet. The height of the object t seconds after it is thrown is given by h(t)=-16t^2+52t+125. Find the average velocity in the first three seconds after the object is thrown.

Answer 1

give me a minute im trying to work out all the math

Answer 2

ok

Answer 3

do you have options

Answer 4

no it'd an assignment where I have to work it out

Answer 5

ok

Answer 6

do you know how to work it out you just dont know the answer?

Answer 7

I don't know either. I'll just ask my teacher in class

Answer 8

ok well the answer is 18

Answer 9

how did you get 18?

Answer 10

idk i just looked at it and got 18, I did mental math some how and got 18

Answer 11

I don't think that's right, because it has a formula.

Answer 12

the average velocity in the first three seconds after the object is thrown Would be 18

Answer 13

have your teacher help you but im sure my answer is right

Answer 14

The velocity at time t s given by the derivative of h(t)

V = -32t + 52

Answer 15

so at time 0 v = 52 and at time 3 , V = -(32)3 + 52 = - 44 ( at this time the object is descending)

Answer 16

Thanks for explaining, is there another step I need?

Answer 17

they are asking for the average velocity Hmmm Im not sure if we can use these 2 results to get that...

Answer 18

its 18

Answer 19

How did you get that?

Answer 20

just trust me

Answer 21

I'm confused now

Answer 22

\(h(0) = 125\)
\(h(3) = 137\)

Net ***Displacement*** over the 3 second period \(= 137 - 125 = 12\)

Ave Velocity over that period \(= \dfrac{12}{3} = 4\)

Answer 23

units....ft/ sec

Answer 24

How did you get the 137?

Answer 25

starfish comand

Answer 26

it's h(3), the height at t = 3

Answer 27

yea thats the correct method of course. I guess you cant average velocities if an object is accelerating.

Answer 28

the displacement from the original starting point is 12ft and velocity = displacement / time

Answer 29

this is starfish command what do you need bubblez?

Answer 30

@Falconmaster

Answer 31

@sillybilly123

Answer 32

what do you want to know about that formula?

Answer 33

Is formula that @sillybilly123 use?

Answer 34

Because this formula is used for this assignement

Answer 35

basically yes
f(b) and f(a) will be the values of h(t) at times 3 and 0 and b-a = 3 - 0

Answer 36

137 - 125

Answer 37

follow?

Answer 38

average velocity = [ (h3) - h(0) ] / (3-0) = (137 - 125) / 3 = 12/3 = 4

Answer 39

so the answer is 4?

Answer 40

@celticcat

Answer 41

yes

Answer 42

starfish command

Answer 43

Yes for the answer being 4?

Answer 44

Sorry I'm a little slow.

Answer 45

i have no freaking clue because im only in middle school

Answer 46

you can just look at my beautiful PFP