Part 02 · Newton's laws and forces · Card 9 of 10
Tension
The pulling force along a rope or string. An ideal light rope has the same tension all along it.
Last updated
Analogy
A rope in tug of war is tight everywhere.
Example
Hanging bucket
T = mgT = 5 kg x 9.8 m/s^2T = 49 N
In practice
A 5 kg bucket hanging at rest from a rope has 49 N of tension.
Questions people ask
Is the tension the same on both sides of a pulley?
For an ideal pulley with no mass and no friction, yes. The rope transmits the same tension on both sides. In real pulleys that have mass, the tension differs because the pulley must be spun, and the difference supplies the torque that turns it.
Can a rope push?
No. A rope can only pull along its length. If you push on its end, it just goes slack. Tension is always a pulling force directed away from the object along the rope. For pushing along a line you need a rod or a spring.