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Grade 11Mechanics

A yo-yo falls to the bottom of its cord and then climbs back up. (a) Does it reverse its direction of rotation at the bottom? Explain your answer. (b) What pulls the yo-yo back to the top?

Profile image of Radhika Batra
11 Years agoGrade 11
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1 Answer

Profile image of Kevin Nash
11 Years ago
(a) The direction of the yo-yo does not reverse at the bottom. When the yo-yo reaches the bottom, it maintains its angular momentum, therefore its angular velocity vector points in the same direction.
When the jerk is given by the person, the yo-yo winds to the thread again and come upwards while maintaining the same direction of rotation.
(b) The yo-yo winds again because of the friction forces between the thread and the surface of the axle. The person jerks the yo-yo when it is at the bottom so that the thread can come in contact with the axle of yo-yo, and instead of sliding over the thread, the axle start to wind up.