# Physics Help Pleaase

1. Feb 22, 2007

### help444

Physics Help!! Pleaase

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

A mass, m, traveling at a speed v, strikes another mass = 2m at rest. After the collision, the first mass, m, is delfected through 45 degrees and has a final speed of v/2.
Find the speed and Direction of the mass 2m after this collision.

2. Relevant equations
p =mv

3. The attempt at a solution

2mfsinT = -mv/2sin 45
mv+2m+ 0 - mv xdr
mv = mv/2cos45+2mfcosT

Anyone help ..

2. Feb 22, 2007

### hage567

I'm guessing you are trying to use conservation of momentum. What is f? What is xdr? Why do you only have a 2m there in the second line? Actually, that second line isn't even an equation! You need to start by drawing a diagram and breaking it up into x and y components, before the collision and after.

3. Feb 22, 2007

### help444

I have
let theta of missing angle = x
v2 = velocity of second mass , 2m
cos45mv/2 + cosX = mv
sin45mv/w= sin X 2Mv2
I can't solve it now..

4. Feb 23, 2007

### hage567

"cos45mv/2 + cosX = mv"

There should be a term for the velocity of the 2m mass in front of the cosX.

"sin45mv/w= sin X 2Mv2"

I'm assuming the w is really a 2??

Everything looks OK I think. You have two equations and two unknowns (not counting the v that is the initial velocity). So put the second equation in terms of one of the unknowns and plug it into the first equation. Solve for that unknown.