Centre of mass of velocity (q61)

AI Thread Summary
The discussion revolves around calculating the center of mass of velocity for two masses moving at different speeds. The formula used is (m1*v1 + m2*v2) / (m1 + m2), but there is confusion about how this leads to the final result. Conceptually, if both masses move at the same speed, the center of mass speed equals that speed; however, if one mass moves faster, the center of mass speed must adjust accordingly. The participants explore how varying speeds of the masses influence the center of mass speed, affirming the need for a balance based on mass distribution. Understanding these dynamics clarifies the relationship between individual velocities and the center of mass.
jack1234
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Hi, for the following problem
http://tinyurl.com/249gz8
the answer is d

What i have done is
Centre of mass of velocity
=(m1*v1+m2*v2)/(m1+m2)

but I am not sure how does it leads to the result d...
can anybody help on this?
 
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It might be easier to view this conceptually. What if both masses had a speed of v1? Then the speed of the center of mass would be v1, right? But some of the total mass (m2) is moving faster, so what must happen to the speed of the center of mass?

And it works the other way as well. What if both masses had a speed of v2. Then the speed of the center of mass would be v2? But some of the total mass (m1) is moving slower, so what must happen to the speed of the center of mass?
 
I see, thanks for the help :)
 

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