An Auto Mechanic Is Attempting to Loosen a Bolt in an Engine

Multiple Choice

An auto mechanic is attempting to loosen a bolt in an engine using a large wrench,but to no avail.If she applies a force of 510N perpendicular to the wrench she is using,applied at 0.75m from the axis of rotation of the bolt,what is the value of the friction force applied to the outer surface of the bolt's threads? The threaded portion of the bolt has diameter 1.2cm.

A) 3.2 kN
B) 510N
C) 32kN
D) 1.6kN
E) 16kN