IMO 1985 LL NOR62

A “large” circular disk is attached to a vertical wall. It rotates

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IMO 1985 LL NOR62

Origin: NOR

Problem

A “large” circular disk is attached to a vertical wall. It rotates clockwise with one revolution per minute. An insect lands on the disk and immediately starts to climb vertically upward with constant speed \pi 3 cm per second (relative to the disk). Describe the path of the insect (a) relative to the disk; (b) relative to the wall.