1-4 What is friction?
OBJECTIVE: Identify examples of friction.
Key Terms
friction: force that opposes the motion of an object
air resistance: force that opposes the movement of an object in air
Lesson Summary
• To stop a moving object, a force must act in the direction opposite to the direction of motion.
• A force that opposes the motion of an object is called friction.
• The force that opposes the downward motion of objects falling through Earth’s atmosphere is called air resistance.
• Some examples of friction include sliding friction, air resistance, and rolling friction.
Key Terms
friction: force that opposes the motion of an object
air resistance: force that opposes the movement of an object in air
Lesson Summary
• To stop a moving object, a force must act in the direction opposite to the direction of motion.
• A force that opposes the motion of an object is called friction.
• The force that opposes the downward motion of objects falling through Earth’s atmosphere is called air resistance.
• Some examples of friction include sliding friction, air resistance, and rolling friction.