1. Torque Is the Turning Effect of a Force

Torque describes how effectively a force can rotate an object around an axis. For example, pushing a door near its handle produces more turning effect than pushing it near its hinges, assuming the same perpendicular force is applied.

2. Torque Depends on Distance

The farther a force is applied from the axis of rotation, the greater the torque it can produce. This is why a long wrench usually makes it easier to loosen a tight bolt than a short wrench.

3. Torque Has a Standard SI Unit

The SI unit of torque is the newton-meter (N·m). One newton-meter is produced when a force of one newton acts perpendicularly at a distance of one meter from the axis of rotation.

4. Torque and Force Are Not the Same

Force can push or pull an object, while torque describes the turning effect of a force. A force may be large but produce little or no torque if its line of action passes directly through the axis of rotation.

5. The Angle of Applied Force Matters

A force produces its greatest torque when applied perpendicular to the lever arm. If the force acts along the lever arm toward or away from the axis, its torque about that axis is zero.

6. Door Handles Are Positioned Away from Hinges for a Reason

Door handles are generally placed far from the hinges to increase the lever arm. This allows a relatively small force to create enough torque to open or close the door.

7. Engines Use Torque to Turn Wheels

Vehicle engines produce torque that is transmitted through the drivetrain to rotate the wheels. The torque available at the wheels also depends on the transmission and final-drive gear ratios.

8. Torque and Horsepower Are Different

Torque measures the turning effect of a force, while power measures how quickly work is performed or energy is transferred. In rotating systems, power depends on both torque and angular velocity.

9. Gears Can Increase Torque

A gear system can increase output torque by trading rotational speed for turning force. In an ideal gearbox, increasing torque through a reduction in speed does not increase the total power.

10. Torque Is Important in Electric Motors

Electric motors generate torque to rotate fans, pumps, washing machines, industrial equipment, and electric vehicles. The amount of torque available at different speeds affects how a motor performs its intended task.

11. Torque Can Be Clockwise or Counterclockwise

Depending on the chosen coordinate convention, torque can be described as clockwise or counterclockwise. In a common two-dimensional convention, counterclockwise torque is positive and clockwise torque is negative.

12. Tightening Bolts Requires the Correct Torque

Engineers specify tightening torque for many bolts and fasteners. Applying too little torque may result in an insecure connection, while applying too much can damage threads, stretch bolts, or break components.

13. Torque Helps Explain How Seesaws Work

A seesaw balances when the clockwise and counterclockwise torques about its pivot are equal. A lighter person can balance a heavier person by sitting farther from the pivot.

14. Torque Is Essential in Robotics

Robotic arms and joints require torque to move loads and maintain positions. Engineers calculate the necessary torque to ensure that motors can move objects safely and accurately.

15. Torque Is Closely Related to Angular Momentum

Torque changes an object's angular momentum. This relationship helps explain rotational motion in systems ranging from spinning wheels to planets and spacecraft.