Question

The height in meters of a projectile can be modeled by h = -4.9t2 + vt + s where t is the time (in seconds) the object has been in the air, v is the initial velocity (in meters per seconds) and s is the initial height (in meters). A soccer ball is kicked upward from the ground and flies through the air with an initial vertical velocity of 4.9 meters per second. After how many seconds does it land approximately?

Answer 1

isn't it -16t

Answer 2

yeah but this is the actual question

Answer 3

maybe try with -16t

Answer 4

using the quadratic equation below:

Where ax^2 + bx + c = 0, x = (-b + sqrt(b^2 -4ac))/2a & x = (-b - sqrt(b^2 -4ac))/2a

I'll leave the calculations to you.

Answer 5

please help me solve

Answer 6

please I am stumped

Answer 7

wait @hba you copy and pasted an answer

Answer 8

the equation you have posted is the equation where the unit of distance measure is meters. the one with the -16 is the one with feet as the distance unit.

Answer 9

they're the same, in other words...

Answer 10

can you help me solve it?

Answer 11

yeah... just plug in the initial velocity for v and s is the initial height...
can you give me these values:

initial velocity, v =
initial height, s =
???

Answer 12

I have no idea

Answer 13

read the problem...

Answer 14

that is the question as I got it

Answer 15

the problem gives you the initial velocity...

Answer 16

4.9 m?

Answer 17

Velocity not distance...

Answer 18

well 4.9 meters per second... that's the initial velocity..
so for now, the equation is : \(\large h=-4.9t^2+\color {red}{4.9}t+s \)

now can you give me the value of s?

Answer 19

HINT: the ball is kicked from the ground

Answer 20

s is your initial height, since it is kicked from the ground, what height is it when it's on the ground?

Answer 21

what is the height of the sole of my feet when i'm standing?

Answer 22

what' the altitude of the ground measured starting from the ground?