What term describes the power applied to make a rotary device rotate?

• A. Linear power
• B. Spin power
• C. Rotary power
• D. Torque power

Answer: (C)

Rotational power is the term that describes the power causing a device to turn. In rotation, the driving factor is torque—the turning effort—while power represents how quickly energy is being transferred as the device spins. The relationship is P = τ × ω, meaning power equals torque times angular velocity. This shows that rotation involves both how hard you push to turn and how fast it turns.

Linear power describes motion along a straight line, so it doesn’t apply to rotation. Spin power isn’t a standard term in engineering practice, and torque power isn’t used because torque is the turning force and power is the rate of energy transfer; the conventional way to describe rotation-related power is rotary (or rotational) power.