A dentist’s drill experiences two separate operating intervals
PHYSICS · Multi-part · CBSE · Physics · System of Particles and Rotational Motion · System of Particles and Rotational Motion
Problem
A dentist’s drill experiences two separate operating intervals.
• Interval 1: The drill motor exerts a constant torque of 0.40 N·m, causing the drill bit to rotate 1.50 full revolutions in the forward direction.
• Interval 2: To remove debris, the motor reverses and exerts a constant torque of 0.25 N·m, causing the drill bit to rotate 2.40 full revolutions in the opposite direction.
Treat the drill bit as the system of interest and neglect any frictional torques.
(a) Calculate the rotational work done on the drill bit during Interval 1. Include the algebraic sign of the work and appropriate units.
(b) Calculate the rotational work done on the drill bit during Interval 2. Include the algebraic sign of the work and appropriate units.
(c) Determine the net rotational work done on the drill bit over both intervals combined. State whether the drill bit gains or loses mechanical energy overall and justify your conclusion.