(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

In this exercise we used steel and glass balls to calculate and prove the conservation of momentum in elastic collisions. I had to prove how momentum is conserved through displacements vectors and right triangles. All that stuff is easy and I got it. The last question is where I am stuck. The question states: When the mass of the 2marbles (glass and steel) are not the same, and they collide (the glass marble was initially at rest), why do you need to use the formula Pglass = (mglass/msteel) x Vglass (in the brackets the mass of the glass marble is divided by the mass of the steel marble, but we are not given any variables and are just required to prove or derive this formula)?

2. Relevant equations

I attempted to derive this formula through P total initial= P total final and the conservation of kinetic energy. 1/2m1v1i^2(squared) + 1/2m2v2i^2 = 1/2m1v1f^2 + 1/2m2v2f^2

3. The attempt at a solution

when i expand the formulas and substitute them into each other, I just end up with the equations for 1D elastic collisions v1f=(m1-m2/m1+m2)v1i and respectively v2f=(2m1/m1+m2)v1i

I spent the whole night going through all 3 of my physics textbooks and many websites online but couldn't find the way to prove or derive that formula. My teacher said it was a hard question but I never thought it would be this difficult. Oh by the way this is Gr.12 Academic physics.

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

2. Relevant equations

3. The attempt at a solution

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# Proving the conservation of momentum when two masses are not equal

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