What would happen? Explain your observations.

If you tie two tennis balls together with a string about a foot long, mark the center of the string with bright ink or attach a brightly colored sticker to it, and hold one ball and let the other hang down and throw it in a ballistic trajectory.

1 Answer
Feb 3, 2018

I think that the system will rotate during the flight while the center of mass (marked by the bright ink) will describe a parabolic trajectory simmilar to the one of a projectile.


The set up seems to me representative of the center of mass situation, the two tennis balls having the same mass and at a fixed distance representing our system. In between of them, along the string, will be placed the center of mass of the system that behaves as a representative of the system during the flight. Exactly as a point mass it will obey to the laws of Dynamics (Newton) and Kinematics.
Regardless of the rotation of the entire system the center of mass as a point will perform as a projectile:

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