Question

A solid cylinder of mass 1.6 kg and radius 35 cm is rotating counterclockwise around a vertical axis running through the centers of its circular faces at 560 rev/min. A second solid cylinder of the same mass and radius is rotating clockwise around the same vertical axis running through the centers of its circular faces at 850 rev/min. If the cylinders couple so that they rotate about the same vertical axis, what is the angular velocity (in rev/min) of the combination? (Indicate the direction with the sign of your answer.)

Answer 1

negative sign shows that direction of rotation of this combination is "clockwise".