Suppose I have a plate and a barbell like the ones we see in the gym. When I spin the plat in the clockwise direction, the barbell also starts spinning in the clockwise direction. When I put my hand on the barbell, stopping its rotation, the plate still rotates clockwise but gains linear velocity and moves off to the right side of the barbell. I thought the cause of this was the torque the bar exerts on the barbell, but when I redid the experiment but with the plate and barbell spinning counterclockwise. The plate still moves to the right side, I expected the plate to move to opposite sides due to the different direction of rotation. Could someone provide me some proof as to why this happens and what are the forces involved. Maybe even a derivation of the equation of motion of the plate.
1 Answer
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My best guess is that the plates on either side cause the material of the barbel to somewhat bend down at the sides and this slight incline is more likely to cause the plate to move in that direction when it is in relative motion and less "locked in" to the material of the barbel.
