Solving Collisions with angles problem

[AceInfinity]

First off, i'd like to note that this isn't homework, and I've seen other threads in here that deal with question/equation/problems, so I hope this isn't against the rules. I found this on a practice physics test online. I'm just using it for the benefit of my knowledge, nothing more.

I can provide the link if necessary for proof.

Heres the question I want to know how to solve:
[PLAIN]http://k.min.us/ibDXoi.jpg

 

[tiny-tim]

Hi AceInfinity!

As you know, you need to use conservation of https://www.physicsforums.com/library.php?do=view_item&itemid=53".

Momentum is a vector, so this is a vector equation, which means the components of momentum in any direction are conserved.

So choose a suitable direction ……

what do you get? ​

 

[AceInfinity]

ohhh... I think you put me on the right track for beginning to solve this. The initial momentum was

in this case. Therefore the conservation of momentum is seen for that X component, I'll have to split them off into the X and Y components of momentum and look specifically at the X/horizontal component of momentum to use the conservation of momentum, if I'm not mistaken?

4.85 Cos(36^o) = 3.92m/s

p = mv
p = (0.200kg)(3.92m/s)
p = 1.2kg•m/s

Solve for momentum of that object.

p = mv
p = (0.200kg)(3.92m/s)
p = 0.784kg•m/s

Momentum of the other object (puck 2) is: 1.2kg•m/s - 0.784kg•m/s

= 0.416kg•m/s [Important: in the x/horizontal direction. need to solve for the angle'd direction]

0.416kg•m/s ÷ [cos(54^o)] =

0.707741472...kg•m/s !

I think with "their" answer, they rounded a bit too early.​

 

[tiny-tim]

Hi AceInfinity!

Momentum of the other object (puck 2) is: 1.2kg•m/s - 0.784kg•m/s

= 0.416kg•m/s [Important: in the x/horizontal direction. need to solve for the angle'd direction]

0.416kg•m/s / [cos(54^o)] =

0.707741472...kg•m/s !

yes that's fine

but there are quicker ways of doing it …

you could take components in the y direction or in the final direction of puck 2 …

(both are quicker because they reduce the number of terms)

try both of those ​