# Velocity of the center of mass

I am having a tough time with this one...
Body A of mass 4 kg is moving in the +x-direction with a speed of 15 m/s. Body B of mass 5 kg is moving in the -y-direction with a speed of 8 m/s. What are the x- and y-components of the velocity of the center of mass of the two bodies?
How do I relate CM and velocity?

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OlderDan
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wolly6973 said:
I am having a tough time with this one...
Body A of mass 4 kg is moving in the +x-direction with a speed of 15 m/s. Body B of mass 5 kg is moving in the -y-direction with a speed of 8 m/s. What are the x- and y-components of the velocity of the center of mass of the two bodies?
How do I relate CM and velocity?
I assume you know how to calculate the center of mass if given the masses and positions of two objects. In this problem the objects are moving with constant velocity, so the positions will be changing with time. Write the equation of motion for each object, and use the position expressions in the CM equation. With a little rearrangement, you will have the equation of motion for the CM

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Thanks for the help. Your explanation made it very easy to comprehend. I appreciate it.