Magnitude of the total momentum of both blocks

[isukatphysics69]

Homework Statement

Find magnitude of momentum of both blocks

Homework Equations

p=mv

The Attempt at a Solution

I am doing my homework right now and just need help understanding finding the total momentum given a before collision/ after collision situation. So i am unsure if i should take the momentum of the whole system from before and after by adding them together and then find the momentum based off of that? That is what i am thinking
Given a before after situation like this

 

[isukatphysics69]

wait since momentum is conserved i think i can just take the momentum of either the before or after part of the collision

 

[isukatphysics69]

i just tested it using graphical method and i realized i can use either the momentum of the before or after collision.

 

[isukatphysics69]

it does not matter