Examples of rotational equilibrium include a ceiling fan rotating at a constant speed or a door opening/closing with constant angular velocity.
Rotational equilibrium occurs when the net torque acting on an object is zero. Torque is a twisting force that causes rotation. When the sum of all torques is zero, the object will either remain at rest (static rotational equilibrium) or continue rotating at a constant angular velocity (dynamic rotational equilibrium). This condition of zero net torque results in zero angular acceleration.
Examples According to the Reference
Based on the provided reference, specific movements are highlighted as examples of rotational equilibrium:
- Ceiling Fan Movement: A key example is the movement of a ceiling fan. The reference states that "ceiling fan movement is the rotational equilibrium movement in which a fan moves around its axis in constant velocity if no force is applied to the rotation point." This describes a ceiling fan spinning at a steady speed. While external forces like air resistance and the motor's force are present, the net torque is zero, allowing it to rotate at a constant velocity.
- Door Opening and Closing: The reference also lists "Door opening and closing" as examples of rotational equilibrium movement. When a door swings at a constant speed (or is held open/closed at rest), the net torque around its hinges is zero.
The reference also mentions a screwdriver as an example of "static rotational equilibrium movement," although its description in the reference regarding torque causing angular acceleration appears contradictory to the definition of equilibrium. However, focusing on the clearer examples provided:
Summarizing the Reference Examples:
- Ceiling Fan: Represents rotational equilibrium when spinning at a constant angular velocity.
- Door: Represents rotational equilibrium when opening or closing at a constant angular velocity or when held stationary (static equilibrium).
These examples illustrate that rotational equilibrium is achieved when torques are balanced, allowing for motion at a constant angular velocity or a state of rest.
