# Magnitude of Momentum, relative to the center of mass (1 Viewer)

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#### gap0063

1. The problem statement, all variables and given/known data
A 4.39 g particle is moving at 4.15 m/s toward a stationary 9.64 g particle.

(a)With what speed does the heavier particle approach the center of mass of the two particles?
Answer in units of m/s.

(b) What is the magnitude of the momentum of the lighter particle, relative to the center of mass?
Answer in units of Ns.

2. Relevant equations
m1v1+m2v2/m1+m2

and

P=mv

3. The attempt at a solution
I got part (a) by using m1v1+m2v2/m1+m2
where v2 is zero

so I got 1.29854 m/s which is right (this is a online hw assignment)

for part (b) I thought it was the mass of m1= 4.39 g= 0.00439 kg

and I times it by the speed I found from part (a) but the number I'm getting isn't right (0.006402 Ns)

so what am I doing wrong?

#### ehild

Homework Helper
You found the speed of the centre of mass with respect to the ground. Calculate the velocity of the lighter particle with respect to the centre of mass.

ehild

#### gap0063

You found the speed of the centre of mass with respect to the ground. Calculate the velocity of the lighter particle with respect to the centre of mass.

ehild
oh yes, thanks!!!

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