How Do You Calculate the Momentum of a Particle Relative to the Center of Mass?

[bmoore509]

Homework Statement

A 3.64 g particle is moving at 2.58 m/s toward a stationary 10.2 g particle. With what speed does the heavier particle approach the center of mass of the two particles?
Answer in units of m/s.
Answer: 0.67855913 m/s

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

Homework Equations

momentum=mv

The Attempt at a Solution

Since its in Ns, I'd use 0.00364kg.
Momentum=0.00364*0.67855913
= 0.002469955

Which the online homework said wasn't right. So I tried using 3.64 and got 2.46995523 which isn't right either.

I don't understand what I'm doing wrong.

 

[bmoore509]

If p=m*vc then the total momentum I got to be 9.3912, the big particle 6.9212601 and the small particle 2.46.

Can someone please help me figure out how this isn't right?

 

[PhanthomJay]

Homework Statement

A 3.64 g particle is moving at 2.58 m/s toward a stationary 10.2 g particle. With what speed does the heavier particle approach the center of mass of the two particles?
Answer in units of m/s.
Answer: 0.67855913 m/s

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

Homework Equations

momentum=mv

The Attempt at a Solution

Since its in Ns, I'd use 0.00364kg.
Momentum=0.00364*0.67855913
= 0.002469955

Which the online homework said wasn't right. So I tried using 3.64 and got 2.46995523 which isn't right either.

I don't understand what I'm doing wrong.

The question asks for the magnitude of the momentum of the lighter particle, relative to the center of mass. The speed of the lighter particle with respect to the center of mass is not .678 m/s. That was the speed of the heavier particle with respect to the center of mass. The momentum of each particle with respect to the center of mass should be the same.

 

[bmoore509]

I eventually got it.