# Before and after collision

1. ### sweedeljoseph

42
1. The problem statement, all variables and given/known data

Two objects of masses M1 = 1 kilogram and M2 = 4 kilograms are free to slide on a horizontal frictionless surface. The objects collide and the magnitudes and directions of the velocities of the two objects before and after the collision are shown on the diagram below. (sin 37$$\circ$$ = 0.6, cos 37$$\circ$$ = 0.8, tan37$$\circ$$ = 0.75).

*PICTURE ISNT WORKING SO HERES THE LINK*
http://img359.imageshack.us/img359/1051/probfk9.jpg

a) Calculate the x and y components (px and py, respectively) of the momenta of the two objects before and after the collision.
b) Show, using the data from the previous question, that linear momentum is conserved in this collision.
c) Calculate the kinetic energy of the two-object system before and after the collision.
d) Is kinetic energy conserved in the collision?

2. Relevant equations
p=mv
m1*v1+m2*v2=m1'*v1'+m2'*v2'
ke=1/2mv2

3. The attempt at a solution
i dont have all the answers from the teacher. i know how to do part a. but thats it. i dont know what else im supposed to do after that.

the answer to part a is:

you just use the p=mv to solve for everything.

i dont know how to do the rest. i think youre supposed to use the other formula i gave but i dont know. i need alot of help.

thank you!
sweedeljoseph

Last edited: Nov 13, 2008
2. ### Hootenanny

9,681
Staff Emeritus
You simply need to do what the question says, can you calculate the kinetic energy of the system before the collision?