Air resistance

Definition

Air resistance is a force that opposes the motion of an object through the air. It depends on the object's speed, surface area, and shape.

5 Must Know Facts For Your Next Test

1. Air resistance increases with the square of an object's velocity.
2. It acts in the direction opposite to the object's motion.
3. In projectile motion, air resistance affects both horizontal and vertical components of velocity.
4. The drag coefficient is a dimensionless number representing an object's resistance to air flow.
5. Terminal velocity is reached when the force of air resistance equals the force of gravity.

Review Questions

• How does air resistance affect the horizontal and vertical components of a projectile's motion?
• What factors influence the magnitude of air resistance acting on an object?
• Explain how terminal velocity is achieved in terms of forces.

Related terms

Drag Coefficient:

A dimensionless number that quantifies an object's aerodynamic resistance.

Terminal Velocity:

The constant speed that a freely falling object eventually reaches when the force of air resistance equals the force of gravity.

Projectile Motion:

The motion of an object thrown or projected into the air, subject to only gravitational acceleration and, if applicable, air resistance.