zuai-logo
zuai-logo
  1. AP Physics C Mechanics
FlashcardFlashcardStudy GuideStudy Guide
Question BankQuestion Bank

Conservation of Energy

Mary Brown

Mary Brown

7 min read

Listen to this study note

Study Guide Overview

This study guide covers the Law of Conservation of Energy, including the mathematical representation ME = K + U with kinetic (K) and potential (U) energies. It discusses conservative and nonconservative forces and their impact on mechanical energy, along with applying conservation of energy to various scenarios. The guide provides exam tips and common mistakes to avoid. Finally, it includes practice multiple-choice and free-response questions focused on energy conservation and the work-energy theorem.

#AP Physics C: Mechanics - Energy Review πŸš€

Hey! Let's get you prepped for the exam with a super-focused review of energy. We'll break it down, make it stick, and get you feeling confident. Let's do this!

#Conservation of Energy: The Big Picture

#The Core Idea

At its heart, the Law of Conservation of Energy states that:

In a closed system, the total energy remains constant. Energy can transform from one form to another, but it cannot be created or destroyed.

Think of it like this: you have a fixed amount of money, you can exchange it for different currencies, but the total amount remains the same. πŸ’‘

  • Key Concept: Energy is a conserved quantity. It's all about transfers and transformations, not creation or destruction.
  • Forms of Energy: Kinetic (motion), potential (position), thermal (heat), chemical, nuclear, etc. All are part of the total energy.

#Mathematical Representation

The total mechanical energy (ME) of a system is the sum of its kinetic energy (K) and potential energy (U):

ME=K+UME = K + UME=K+U

  • Kinetic Energy (K): Energy of motion. K=12mv2K = \frac{1}{2}mv^2K=21​mv2
  • Potential Energy (U): Stored energy due to position or configuration. Examples include gravitational potential energy (Ug=mghU_g = mghUg​=mgh) and spring potential energy (Us=12kx2U_s = \frac{1}{2}kx^2Us​=21​kx2).

#Work and Nonconservative Forces

When nonconservative forces (like friction or air resistance) do work on a system, the total mechanical energy changes. The work done by these forces is:

Ξ”ME=Wnonconservative\Delta ME = W_{nonconservative}Ξ”ME=Wnonconservative​

  • Important Note: This work can either add or remove energy from the system.
  • Conservative vs. Nonconservative: Conservative forces (gravity, spring) conserve total mechanical energy; nonconservative forces do not.

#

Key Concept

Applying Conservation of Energy

In a conservative system (where only c...

Feedback stars icon

How are we doing?

Give us your feedback and let us know how we can improve

Question 1 of 7

A system's total energy is like a fixed amount of money πŸ’°. Which of the following best describes what happens to this energy according to the Law of Conservation of Energy?

It can be created from nothing

It can be destroyed completely

It can transform from one form to another, but the total remains constant

It always increases over time