Question

CAN ANYBODY HELP ME WITH Applications: Projectile Motion Math????



Ted throws an object into the air with an initial vertical velocity of 54 feet per second from a platform that is 40 feet above the ground. About how long will it take the object to hit the ground?

A.
1 second

B.
2 seconds

C.
3 seconds

D.
4 seconds

Answer 1

Im horrible at Projectile Motion equations

Answer 2

I can solve with a given equation, but am not far enough in math to know intuitively what equation to form

Answer 3

oh

Answer 4

I know the form but not the values to insert

Answer 5

Are we assuming its shot straightforward and not at an angle? O.o

Answer 6

Idk

Answer 7

vertical velocity of 54 feet per second from a platform that is 40 feet above the ground

for being descriptive it's vague.

Answer 8

Its vertical

Answer 9

Oh, straight up then.

Answer 10

Straight up then how long will it take to get down??

Answer 11

I dont remember any kinematic equations, but im sure you can use one of them. Do you have any kinematic equations from lecture or a text?

Answer 12

solve for y=-40

Answer 13

So remember I dont get any of this.

Answer 14

So you werenever given any kinematic equations?

Answer 15

let me check

Answer 16

" Use the projectile motion formula for when the height is in
feet. Then substitute 0 for h(t), 54 for v0, and 40 for h0.
Disregard the negative solution. "

Answer 17

So looks like you should have SOMETHING. There are usually 3 kinematic equations, so looks like you shoudl have one of them somewhere. Ive never been able to remember them personally.

Answer 18

Dont ask me i just started this stuff

Answer 19

It has nothing to do with how new you are to it, you should have an equation somewhere. You might not know what it is, but you have to have that formula or theresnothign wecan do. If you can find it I can try to help ya.

Answer 20

http://www.calctool.org/CALC/phys/newtonian/projectile

Answer 21

kinematics yummmm. Just google up "kinematic equations for projectile motion" it should easy plug and play

Answer 22

how @OrionsBelt

Answer 23

how to google? Open a browser and type in google.com lol.

Answer 24

no i dont see anything in the "kinematic equations for projectile motion" section and @ehuman sry but idk how to use it

Answer 25

i think its parbola

Answer 26

http://en.wikipedia.org/wiki/Projectile_motion

Answer 27

...

Answer 28

yes it is a parabola even if thrown straight up, that last link has formula for parabola

Answer 29

@Psymon @ehuman its an The initial velocity type of equation

Answer 30

The equation is in @ehuman 's link

Answer 31

Still has to do with kinematics. But trust me, if you find the right formula theres not much thought to it. Youre assumign youre clueless too early before you even have the necessary tools.

Answer 32

@Hero @myininaya can you help us out?

Answer 33

(sigh) I'll just have to guess......

Answer 34

what angle does Ted throws the object?

Answer 35

Vertical...

Answer 36

up or down?

Answer 37

Why is this guy standing there throwing junk in the air anyway?

Anyway
\[-32t^2 + 54t + 40 = 0\]
I think

Answer 38

Up

Answer 39

Lol idk its my question lol

Answer 40

\[y(t)=y(0)+{v_0}_yt+\tfrac12a_yt^2\]

Answer 41

so

Answer 42

y(0) is the initial height , i.e. the height of the platform

v_0_y is the vertical component of the initial velocity

a is vertical component of acceleration , ie - gravity

t is time

Answer 43

Oh, yeah, half.
\[-16t^2 + 54t + 40 = 0\]
Who uses feet in kinematics equations, anyway?
Probably the same kind of person who stands on platforms throwing stuff in the air.