Normal force

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Definition

Intensional definition

Normal force, sometimes called normal reaction, is the component of contact force between two bodies acting in a direction perpendicular to the plane of contact (or the tangent plane at the point of contact). It is in the outward direction on both bodies. The magnitudes of the normal force on both bodies are equal and the directions are opposite, in keeping with Newton's third law.

Tendency-based definition

Normal force is the force exerted by two bodies on each other at a surface of contact that is intended to precisely counteract any tendency the bodies have of moving into each other.

Related forces

  • Friction: It is the component of contact force along the plane of contact.
  • Tension: Tension is a force exerted by a taut string on an object at its end, pulling the object inward.
  • Spring force: Spring force is a force exerted by a spring on an object attached at its end. When the spring is extended, the force is inward, analogous to tension, while when the spring is compressed, this acts outward, analogous to normal force.