Gravitational torque

Definition

Gravitational torque is the rotational force exerted by gravity on an object about a pivot point. It depends on the object's weight, the distance from the pivot, and the angle of application.

5 Must Know Facts For Your Next Test

1. Gravitational torque is given by the equation $\tau = r \times mg \sin(\theta)$, where $r$ is the distance from the pivot, $m$ is mass, $g$ is acceleration due to gravity, and $\theta$ is the angle between the force and lever arm.
2. For an object in static equilibrium, the sum of all torques acting on it must be zero.
3. The lever arm or moment arm is defined as the perpendicular distance from the pivot point to the line of action of the force.
4. Gravitational torque can cause rotational motion if it is not balanced by another torque.
5. In analyzing problems involving gravitational torque, both magnitude and direction (clockwise or counterclockwise) are important.

Review Questions

• What are the components needed to calculate gravitational torque?
• Why must gravitational torque be considered when analyzing static equilibrium?
• How do you determine if an object will rotate based on gravitational torque?

Related terms

Static Equilibrium: A condition where an object remains at rest with no net force or net torque acting upon it.

Moment Arm: The perpendicular distance from a pivot point to the line of action of a force.

Torque: A measure of how much a force acting on an object causes that object to rotate. Calculated as $\tau = r \times F \sin(\theta)$.