Normal force

Definition

The normal force is the perpendicular contact force exerted by a surface on an object resting on it. It counteracts the weight of the object.

5 Must Know Facts For Your Next Test

1. The normal force is always perpendicular to the contact surface.
2. The magnitude of the normal force can change depending on other forces acting on the object.
3. In situations involving inclined planes, the normal force is less than the object's weight.
4. If no vertical acceleration occurs, the normal force equals the gravitational force acting on the object.
5. The normal force plays a crucial role in frictional forces, as friction depends on this force.

Review Questions

• What direction does the normal force act relative to a surface?
• How does an inclined plane affect the magnitude of the normal force?
• What happens to the normal force if additional downward forces are applied to an object?

Related terms

Gravitational Force: The attractive force exerted by Earth on an object, directed towards Earth's center.

Frictional Force: The resistive force that opposes motion between two surfaces in contact.

Inclined Plane: A flat surface tilted at an angle used to demonstrate effects of forces, including components of gravity and normal forces.