#AP Physics 1: Collisions & Center of Mass - The Night Before 🚀

Hey there, future physicist! Let's get you prepped and confident for tomorrow's exam. We're going to break down collisions and center of mass, making sure everything clicks. Ready? Let's dive in!

#1. Collisions: Momentum is Key! 🎯

#1.1 What's a Collision?

A collision is when two or more objects interact, exerting forces on each other for a short period. Think of it like a quick high-five between objects. The most important thing to remember is that momentum is usually conserved during a collision.

Key Concept

Momentum Conservation: If the net external force on a system is zero (or negligible), the total momentum of the system remains constant. This is true for both elastic and inelastic collisions.

#1.2 Types of Collisions

There are two main types of collisions:

Elastic Collisions: Objects bounce off each other, and both momentum and kinetic energy are conserved. It's like a perfect billiard ball hit - no energy is lost to heat or sound.

Quick Fact

Elastic Collision: KE initial = KE final

Inelastic Collisions: Objects either stick together or deform, and kinetic energy is not conserved (some energy is lost to heat, sound, etc.). Momentum is still conserved. Think of a car crash where the cars crumple.

Quick Fact

Inelastic Collision: KE initial ≠ KE final

*   **Completely Inelastic Collisions:** A special type of inelastic collision where objects stick together after colliding.

Memory Aid

Memory Aid: Inelastic collisions are messy (energy is lost), while elastic collisions are clean (energy is conserved).

#1.3 Visualizing Collisions

Inelastic Collision

Inelastic Collision: Objects stick together after the collision, kinetic energy is not conserved.

Elastic Collision

Elastic Collision: Objects bounce off each other, both kinetic energy and momentum are conserved.

#1.4 Solving Collision Problems

Identify the Type: Determine if the collision is elastic or inelastic. T...

Conservation of Linear Momentum