AP Physics 1: Algebra-Based Unit 5 Topic 3: Torque

What to Know

Torque depends on force magnitude, lever arm distance, and angle between them.
A force applied farther from the axis can produce a larger torque.
Only the perpendicular component of force contributes to torque.
Always connect this topic back to the larger unit: Torque and Rotational Dynamics.

Detailed Notes

Torque belongs to Unit 5: Torque and Rotational Dynamics. Torque measures how effectively a force causes or changes rotational motion about an axis. Start by naming the system, choosing axes or a sign convention when needed, and identifying which physical quantity is changing.

Key relationships: Torque depends on force magnitude, lever arm distance, and angle between them. A force applied farther from the axis can produce a larger torque. Only the perpendicular component of force contributes to torque.

Model to use: Draw the axis, position vector, force vector, and perpendicular lever arm before assigning torque direction. A strong model should include labels, directions, units, and the reason each relationship applies.

AP-style move: When comparing torques, use perpendicular distance or perpendicular force component, not just force size. For free-response work, write the principle first, show the setup, and then interpret the result in the physical context.

Key Vocabulary

Torque

The rotational effect of a force about an axis.

Lever arm

The perpendicular distance from the axis to the line of action of a force.

Line of action

The straight line extending along the direction of a force.

Clockwise torque

Torque tending to rotate an object clockwise.

Counterclockwise torque

Torque tending to rotate an object counterclockwise.

Quick Practice

How would you explain Torque in one or two AP-style sentences?

Name the concept, apply it to a specific example or source, and explain the reasoning that connects the evidence to your answer.

Official Alignment

Reference and Attribution

AP Physics 1 concept reference: AP Physics 1: Concise Summary Notes by IITian Academy. EduCompanion used this source as a topic checklist and conceptual reference, then rewrote the study notes in original wording.

AP Physics 1: Concise Summary Notes