Question

Consider a spider walking from the top of a (stationary) beach ball. (Let that angular position =

0
O
.) The spider finds it loses its grip when the normal force between it and the surface is less than 1/2
of its weight. At what angle does this slipping begin?

Answer 1

mg is directed downwards. resolve it into two components: tangential and radial. Radial component is directed opposite to normal force

When N=mg/2, radial component mgcos α=mg/2. Then α=60º.
(this is the position of number”2” on the face of clock assuming that the object started from “12”)