2D momentum of two objects next to a wall

  • Thread starter Thread starter Jeriho
  • Start date Start date
  • Tags Tags
    2d Momentum Wall
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
2 replies · 2K views
Jeriho
Messages
3
Reaction score
0

Homework Statement


We have two pucks next to a wall. Puck 1 has velocity v0=15 m/s in the direction y (as seen on the picture). Puck 2 is stationary. After the collision puck 1 moves in the opposite direction with velocity v1=10 m/s and puck 2 moves with unknown velocity in the direction x. The radius of puck 1 is r1=3cm and of puck 2 r2=6cm. The mass of puck 1 is m1=0.1kg and of puck 2 m2=0.5kg. The collision is not elastic.

What is the velocity of puck 2 after the collision?

http://img134.imageshack.us/img134/8082/breznaslova.jpg

Homework Equations


Equation of momentum P=mv
Pythagorean theorem c2=a2+b2

The Attempt at a Solution


First I calculated the angle using the radiuses of the pucks and I got Cos([tex]\alpha[/tex])=[tex]\frac{r<sub>2</sub>-r<sub>1</sub>}{r<sub>2</sub>+r<sub>1</sub>}[/tex]
I got that [tex]\alpha[/tex] = 70.5 degrees.

Then I went on to figure out momentums. I figured out this:
http://img256.imageshack.us/img256/8120/breznaslova2.jpg
The angle between P0 and P2 is [tex]\alpha[/tex].
Then I went on to make the P1 the hypotenus and the opposite is P1y which is the same as P=m1v1. From that I calculated the angle and then the adjacent P1x. Am I right to think that the velocity I am looking for is vx=[tex]\frac{P<sub>1x</sub>}{m<sub>2</sub>}[/tex].

Thanks for any assistance.
 
Last edited by a moderator:
Physics news on Phys.org
Does no one have an idea how to do this?