Tension (mechanics) facts for kids

In physics, tension is a special kind of pulling force. Imagine pulling on a rope or a string. The force that travels through that rope is called tension. It's like the rope is trying to pull back on whatever is attached to its ends.

Tension can also be seen as two forces working against each other. For example, if you pull on a rope, the rope pulls back on you. This is an action-reaction pair of forces. Tension is often the opposite of compression, which is a pushing force.

Even at a tiny level, like atoms and molecules, tension exists. When these tiny particles are pulled apart, they gain potential energy. They also have a restoring force that tries to pull them back together. This restoring force is another way to think about tension.

Understanding Tension in Physics

Tension is measured in newtons in the International System of Units (SI). You might also hear it measured in pounds-force in other systems. The ends of a string or rope under tension will pull on the objects they are connected to. They pull in the direction the string is pointing. These forces are sometimes called "passive forces."

Tension and Movement

When objects are held by ropes or strings, two main things can happen:

• No Movement: If the objects are not moving or are moving at a steady speed, the total pulling force (tension) is balanced. This means the system is in equilibrium.
• With Movement: If the objects are speeding up or slowing down, there is a net force acting on them. This net force is often due to tension.

Images for kids

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  This image shows a tug-of-war team. The rope they are pulling has tension. The diagram shows how the pulling force, T, acts along the rope. Each part of the rope is pulled by the parts next to it.

See also

In Spanish: Tensión (mecánica) para niños