Normal Force

The normal force is the force exerted by a surface to support the weight of an object resting on it. When an object is placed on a surface, like a book on a table or a person standing on the ground, the surface pushes up on the object with a force equal to the force of gravity pulling the object down. The normal force prevents the object from falling through the surface and determines the apparent weight of the object.

The normal force is always perpendicular to the surface, which means it acts at a right angle to the surface. It is a contact force, meaning it only exists when the object is in contact with the surface. The magnitude of the normal force depends on the weight of the object and the angle of the surface, but it is always equal and opposite to the force of gravity acting on the object.

Study Guide

1. Definition: What is the normal force and how does it relate to the weight of an object?
2. Direction: In what direction does the normal force act on an object resting on a surface?
3. Perpendicularity: Why is the normal force always perpendicular to the surface?
4. Magnitude: How does the magnitude of the normal force change with the angle of the surface?
5. Contact Force: Is the normal force a contact force or a non-contact force? Explain.
6. Apparent Weight: How does the normal force determine the apparent weight of an object?

These questions cover the basic concepts of the normal force and will help you understand and remember the key points of this topic.