Question

The height h in feet of a ball t seconds after being tossed upwards is given by the function h(t)=84t-16t^2.
A. After how many seconds will it hit the ground?
B. What is its maximum height?

The topic of this problem is WORD PROBLEM INVOLVING QUADRATIC FUNCTION

Answer 1

@Loser66 help please?

Answer 2

@akitav

Answer 3

@Nurali

Answer 4

what would be the height of the ball when it hits the ground?

Answer 5

110.25? i'm not pretty sure about my answer @akitav

Answer 6

when the ball is on the ground height = 0, so the function which gives the height at any time would give h(t) = 0.\[84t-16t^2= 0\]taking t out \[t(84-16t) =0 \]so either t = 0 or (84-16t) = 0 which gives us
t = 84/16 = 5.25 seconds (any unit for time given with the question?)

Answer 7

Hmm. I see, isn't 2.63 is the seconds? Am i wrong? :3

Answer 8

the function is \[h(t) = 84t-16t^2\]
right?

Answer 9

yes

Answer 10

then the answer for time when height = 0 or is t = 0 ( at the time of launch) or t = 5.25 seconds.

Answer 11

Ohh. I understand now :) then after you get the seconds? I will substitute the t to the equation h(t)=84t-16t? Am i right or wrong?

Answer 12

correct, for the second part. now one part to think about is the way to get the time for the highest point. it would spend exactly half of its time going up and half coming down. Since it took 5.25 sec in going up and coming down.\[5.25 = 2 \times t'\]solve for t' and put that value for answer to part b).

Answer 13

What formula can i use for part b? Any hint please?

Answer 14

Never mind for the hint :) hihi. I already know. ^_^ thank yooou so much @akitav :)