# Ball Collision Problem

1. Nov 29, 2011

### rzlblrt417

1. The problem statement, all variables and given/known data

a ball hits a wall at 60 degrees from the wall and leaves the wall at 60 degrees.

v1 = 10 m/s
v2 = 10 m/s
m = 3.00 kg
t = 0.200s

2. Relevant equations

p = mvcos(angle)
J = p2 - p1

3. The attempt at a solution

p = (3.00)(10)(cos(60))
p1 = 15
p2 = 15

and that is as far as i can get. I am not sure how time plays into this. Any help is appreciated. I have the text in a few hours. Thank you

2. Nov 29, 2011

### grzz

3. Nov 29, 2011

### sankalpmittal

As grzz said , I cannot understand what you are trying to find out. Anyways what's the question asking for ?

4. Nov 29, 2011

### rzlblrt417

My apologies, I always do that. Force on by the wall on ball

5. Nov 29, 2011

### rzlblrt417

*by wall on the ball

6. Nov 29, 2011

### sankalpmittal

Got that ! Ok so what is p1 ? Or I mean momentum of the ball before striking the wall ?

Then you find out p2 or the momentum of ball after it stroke the wall.

What do you get ?

7. Nov 29, 2011

### rzlblrt417

the same thing for p1 as p2?

8. Nov 29, 2011

### rzlblrt417

14.7n?

9. Nov 29, 2011

### sankalpmittal

No p1 and p2 aren't same. Be careful regarding geometry.

Hint : see the image : http://postimage.org/image/qvnhzhnsl/ [Broken]

Look at image

Last edited by a moderator: May 5, 2017
10. Nov 29, 2011

### rzlblrt417

ok so then

p1 = (3.00)(10)cos(30)
p2 = (3.00)(10)cos(60)

so p2 - p1 = -14.133 so then it would just be 14.133N?

or is it sin(30) making it 14.5N

Last edited by a moderator: May 5, 2017
11. Nov 29, 2011

### sankalpmittal

Correct.

Right !

Nope. What about time t ?
From Newton's second law : F= Δp/Δt = p1-p2/t

Plug in it. What do you get ?
Do calculations properly. You got it wrong for p1-p2 also.

12. Nov 29, 2011

### rzlblrt417

OH! ok so then after plugging everything in i got 71.6N!

13. Nov 30, 2011

### sankalpmittal

Your method of evaluation is correct but calculations are wrong. Do you know the value of cos 60o and cos 30o ? What are they ?