Torque and Angular Acceleration
Torque is the turning effect of a force, t = r x F, and produces angular acceleration through t = I α.
What is Torque and Angular Acceleration?
Torque is the turning effect of a force, t = r x F, and produces angular acceleration through t = I α.
Key formula / rule: t = rF sin p; maximum when the force is perpendicular to the arm.
Key points
- Compute torque about a stated axis.
- Apply t = I α to rotating systems.
Common exam trap
Ignoring the perpendicular distance and using the full force.
Definitions
- Term
Torque and Angular Acceleration
- Meaning
Torque is the turning effect of a force, t = r x F, and produces angular acceleration through t = I α.
- Term
Torque and Angular Acceleration — explanation
- Meaning
Torque depends on where the force is applied, not only on its magnitude. The relation t = I α is the rotational counterpart of F = ma about a fixed axis.
Learning objectives
Compute torque about a stated axis.
Apply t = I α to rotating systems.
Formulae
- Key point
t = rF sin p; maximum when the force is perpendicular to the arm.
- Key point
t = I α for a rigid body about a fixed axis.
- Key point
Torque is a vector along the axis of rotation.
Prerequisites
PHY-U2-ROT-T1-S1-C3
PHY-U1-NLM-T1-S1-C2
Common mistakes
Ignoring the perpendicular distance and using the full force.
Applying t = I α with I taken about a different axis.
Keywords
Torque
Angular
Acceleration
Practice preview
Which of the following expressions correctly defines torque (t) in terms of position vector (r) and force vector (F)?…
easy
What is the SI unit of torque?…
easy
A rigid body with a moment of inertia 'I' about a fixed axis is subjected to a net external torque 't'. What is the resulting angular acceleration 'alpha'?…
easy