Physics: Collison/Momentum Problem
posted by Cicilia .
A 15 kg mass, moving east at 5 m/s, collides elastically with another 10 kg mass, moving west at 1 m/s. After the collision, the larger mass moves off with a velocity of 3 m/s. What is the final velocity of the smaller mass?
Is it 4m/s? Or would it be 2m/s?
Do you add the momentum of the 2 masses because of conservation of momentum or subtract them because they're going in different directions?

conservation of energy.
energy before= energy after
15*5^2+10*1^2=15*3^2+10*v^2
V^2= 1.5*25+11.5*9
v= 5m/s check the math. 
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