Question

David kicks a soccer ball off the ground and in the air with an initial velocity of 35 feet per second. Using the formula H(t) = −16t2 + vt + s, what is the maximum height the soccer ball reaches? (4 points)

17.9 feet
18.2 feet
18.7 feet
19.1 feet

Answer 1

Test? :P

Answer 2

hah no, worksheet

Answer 3

H(t)- height reached at time t right? You will have to differentiate it wrt time to get the velocity at any time t.

Answer 4

Oh no...

Answer 5

wait, why no

Answer 6

hmm.. brb.

Answer 7

ok, cool

Answer 8

you know how to find the maxima of an equation right? suppose i give you an equation y= −16t2 + vt + s, find the value of t for which y is maximum. you'll be able to do it?

Answer 9

yeah, i can

Answer 10

No.. wrong again. wait. i didnt look at constant v..
What we have to first is. differentiate it wrt time. It would give us the velocity equation. we know v at t=0 is 35f/sec, find the constant v.

Answer 11

haha ok

Answer 12

IM A FLYING BOY

Answer 13

So after finding the constant v, plug it back in the equation H(t), differentiate it again, put it equal to zero, you'll get a value of t, the double derivative of the equation would be <0 , so that obv would be the maximum value. Put that time back into the equation of h(t) and find the maximum height.
But... what about constant s? :O

Answer 14

ohh, ok! i have the answer. thanks! @yrelhan4

Answer 15

How did you do it? Find the time period of the whole trajectory and dividing it by 2? Does that work?

Answer 16

i got D. haha not hard

Answer 17

Alright.

Answer 18

How did you do it? :O

Answer 19

uhh, just used my brain

Answer 20

No i mean the method lol.

Answer 21

give up yrelhan shes smarter

Answer 22

ahah i just substituted the numbers into the equation and solved

Answer 23

Ha, of course she's smarter.
I'll note this question down though and try to solve it.

Answer 24

like b=35 a=-16

Answer 25

Hmmm... It would take me time lol. I'm not as smart as you after all.

Answer 26

Its not D. :P

Answer 27

Think about it. Its easy though.
A hint: s should be 0. why?