Initial Velocity Question

  • Thread starter MaNiFeST
  • Start date
  • #1
36
0
Ok So if I were to launch a waterballoon with a waterballoon launcher VERTICALLY , how could I find out the Initial Velocity With OUT a stop watch? My other supplies include a meter stick
 

Answers and Replies

  • #2
3,042
15
Are you familiar with conservation of energy?
 
  • #3
36
0
This is for a lab at school and you get Extra Credit if you can figure out the first part without a stop watch. Would i have to weigh it? And sorry, im not familiar with conservation of energy
 
  • #4
3,042
15
Ok, are you familiar with the equations of motion?
 
  • #5
36
0
I am familiar with the equations for angles ( sin, cos), displacement in X,Y , etc,, for constant/non constant velocities and Trajectories
 
  • #6
3,042
15
Look through them and try to find one that involves the parameters you think are going to be important and post it.
 
  • #7
36
0
This isnt really a homework question but w/e

Thanks again
 
  • #8
36
0
Well if I am shooting an object vertically then Displacment X will be 0m, and
Vy = Vo * sin(90) because the degrees will be 90
VFy = 0 m/s

Thats about all the variables i know atm

Im unsure of which equation to use
 
Last edited:
  • #9
3,042
15
Well, dont solve any equations yet, just look for some that might be useful, and well work from there.
 
  • #10
36
0
Would this work
VFy^2 = VOy^2 + 2a*Displacment Y
 
  • #11
3,042
15
Aha, you are on to something. Keep going.
 
  • #12
36
0
Displacment Y = {(Vo^2+sin(2*angle)} / g

Only other one i know that doesnt involve time
 
Last edited:
  • #13
3,042
15
where did this come from? You were on the right track before. Maybe you should take a closer look at your first equation.
 
  • #14
36
0
its equation for X or Y displacment
I am looking for Initial Velocity (Vo) and those two are the only ones that do not include time because i wont have a stop watch when doing this experiment
 
  • #15
3,042
15
Yes, look at your first equation, and you tell me what each of those terms mean.
 
  • #16
36
0
VFy^2 = VOy^2 + 2a*Displacment Y
I am looking for Initial Velocity and not just VOy
Final Velocity of Y = is 0 m/s in this case
VOy^2 = is unknown
a = 9.81m/s^2 in this case
Displacment Y = is also unknown
 
  • #17
3,042
15
Ok, we need to get this terminology straight.

[tex]V_{fy}[/tex] means the final velocity in the y direction.

[tex] V_{oy} [/tex] means the initial velocity in the y direction.

Does this help at all?

Final Velocity of Y = is 0 m/s in this case

Yes, that's correct. Now when does this occur?
 
  • #18
36
0
VFy That occurs when the object stops right before it comes back down
I Know what the terminology means,
 
  • #19
3,042
15
MaNiFeST said:
VFy That occurs when the object stops right before it comes back down
I Know what the terminology means,

How would a ruler be useful given this information? What is the value of Vfy?
 
  • #20
36
0
Thats the thing, I have almost no idea
 
  • #21
3,042
15
Well, you just said it yourself:

VFy That occurs when the object stops right before it comes back down

What does that mean?
 
  • #22
36
0
It means that in the Y direction, the final velocity is 0 because there is no motion, it suspends in midair
 
  • #23
3,042
15
Exacttttttly. So what does that mean Vfy =?
 
  • #24
36
0
VFy = 0 m/s
 
  • #25
3,042
15
Bingo. Now, think about that ruler. What could you do with that ruler now that you have this new information?
 

Related Threads on Initial Velocity Question

  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
6
Views
1K
  • Last Post
Replies
7
Views
2K
  • Last Post
Replies
11
Views
2K
  • Last Post
Replies
4
Views
887
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
2
Views
924
  • Last Post
Replies
6
Views
606
Top