Rotational Motion and Torque
Torque is the turning force that causes rotation, calculated as force multiplied by its perpendicular distance from the axis.
▶ Interact
Play with the controls to see the idea in action.
📘 Learn
Torque is the turning force that causes rotation, calculated as force multiplied by its perpendicular distance from the axis.
- Larger distance gives larger torque
- Spanners use long handles
- Angular speed measures spin rate
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Rotational Motion and Torque?
Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains Rotational Motion and Torque. Physics topics explain how things move, push, heat up and carry energy, so each one here pairs a definition with a live model you can change.
Check that you can explain Rotational Motion and Torque in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Rotational Motion and Torque explains how the physical world behaves, from sport and transport to electricity and medicine.
Rotational Motion and Torque in detail
Rotational motion describes objects turning about an axis, using angular displacement, angular velocity ω (in rad/s) and angular acceleration. The linear speed of a point at radius r is v = ωr.
Torque, the turning effect of a force, is force times perpendicular distance, and it causes angular acceleration, τ = Iα, where I is the moment of inertia, which depends on how mass is distributed about the axis. Spinning objects have angular momentum, which is conserved: an ice skater spins faster by pulling in their arms.
How the interactive helps you understand Rotational Motion and Torque
Watch the lever in the interactive. Use any sliders or buttons it offers to change the values and see how the lever responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Rotational Motion and Torque.
Real-life uses and examples
- Answer “explain” questions by linking Rotational Motion and Torque to a clear cause and effect.
- Predict what a ball, car or circuit will do with Rotational Motion and Torque before you do the calculation.
- Explain everyday devices, such as brakes, lifts or chargers, using Rotational Motion and Torque.
Common mistakes to avoid
- Forgetting that some quantities, such as force or velocity, also have a direction.
- Mixing up Rotational Motion and Torque with a related quantity that has different units.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Rotational Motion and Torque
What is Rotational Motion and Torque?
Torque is the turning force that causes rotation, calculated as force multiplied by its perpendicular distance from the axis.
What are the most important points about Rotational Motion and Torque?
The main points are: Larger distance gives larger torque; Spanners use long handles; Angular speed measures spin rate.
Why is Rotational Motion and Torque useful?
Understanding Rotational Motion and Torque explains how the physical world behaves, from sport and transport to electricity and medicine.
How can I practise Rotational Motion and Torque?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Rotational Motion and Torque?
Related topics in Physics include Capacitors and Charge Storage, Alternating and Direct Current, Hydroelectric, Geothermal and Tidal Power.