#AP Physics C: Mechanics - Newton's Third Law & Tension Review 🚀

Hey there! Let's get you prepped for the AP Physics C: Mechanics exam. This guide is designed to be your go-to resource for a quick, effective review, especially the night before the test. We'll break down Newton's Third Law and its applications, focusing on what matters most for the exam. Let's dive in!

#Newton's Third Law: Action-Reaction Pairs

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• What it is: For every action, there's an equal and opposite reaction. This means forces always come in pairs. 👯‍♀️
• Formula: $$\vec{F}_{A \text{ on } B} = -\vec{F}_{B \text{ on } A}$$
  • The negative sign indicates the forces act in opposite directions.
  • These forces act on different objects. This is super important!
• Example: When you push on a wall, the wall pushes back on you with the same amount of force, but in the opposite direction.

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- Explains how forces work in pairs during interactions between objects. - Essential for understanding how things move, from rocket propulsion to everyday pushes and pulls. - Helps us understand why internal forces don't affect a system's center of mass motion, while external forces do.

#Internal vs. External Forces

#Internal Forces

• Definition: Forces between objects within a system. Think of the forces between molecules in a solid.
• Key Point: Internal forces do not affect the motion of the system's center of mass. They cancel each other out within the system.

#External Forces

• Definition: Forces between an object in the system and something outside the system. Gravity pulling down on an object is a great example....