A mechanic uses a long-handled torque wrench to loosen a rusted bolt
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Energy and Momentum of Rotating Systems · Energy and Momentum of Rotating Systems
Problem
A mechanic uses a long-handled torque wrench to loosen a rusted bolt. A constant wrench torque is exerted on the bolt, causing it to rotate slowly through a small angle before stopping again.
Assume friction within the bolt–nut interface is the only mechanism resisting rotation. Ignore any heating or sound losses that do not arise from this friction.
(a) Describe qualitatively how energy is transferred between the mechanic, the bolt–nut system, and the surroundings while the bolt is turning.
(b) If the mechanic had instead applied the same magnitude of torque in the opposite rotational direction and the bolt still rotated by the same angle, explain whether the sign of the work done by the torque would change and why.
(c) Discuss how the sign of the calculated work relates to whether energy is added to or removed from the bolt–nut system.