An ant walks down the surface of a ball. If the ant begins to slip when the normal force is less than one-third of the ant's weight, at what angle, measured from the top of the ball, does the ant begin to slip?
A) 70.5°
B) 19.5°
C) 55.0°
D) 18.4°
E) 35.2°

Question

Quizplus · Accepted Answer

The ant begins to slip when the normal force is less than one-third of the ant's weight. This occurs when the angle between the normal force and the weight is greater than 60 degrees. The angle measured from the top of the ball is 180 degrees minus the angle between the normal force and the weight, which is 180 degrees minus 60 degrees, or 120 degrees.

An Ant Walks Down the Surface of a Ball