Pulleys are best described as:

• A. They regulate voltage
• B. They store energy
• C. They measure power
• D. They are wheels used to transmit power from a motor to drive the roller of a conveyor belt

Answer: (D)

Pulleys are wheels with grooves that guide a belt or rope to transfer motion from a motor to another component, such as the conveyor drive roller. This setup lets the motor’s torque move the roller without a rigid shaft connection. The belt and pulley sizes also let you change speed and torque: a smaller driving pulley can reduce speed but increase torque on the driven roller, while a larger driving pulley does the opposite. Pulleys aren’t about electrical control, energy storage, or measuring power, which is why they’re described as wheels used to transmit power from a motor to drive the conveyor roller.