Contact forces result from the interaction of one object touching another object, and they arise from interatomic electric forces. These forces include tension, friction, normal, spring (Physics 1), and buoyant (Physics 2).

Let's review some basic contact forces from Physics 1 and remind ourselves of what they are!

Some other basic concepts not specifically in the AP Physics 2 curriculum but the writers may ask you to recall from Physics 1! 

where μ (Greek letter mu) is the coefficient of either static or kinetic friction and N is the normal force. 

Friction is present if a problem mentions a “rough” surface, or specifically states the coefficient of static or kinetic friction.

AP Physics 2

Learn everything you need to know about unit 1, fluids, in AP Physics 2 with our resources! Study density, fluid pressure and forces, conservation of energy in fluid flow, buoyancy, and conservation of mass flow rate in fluids with our trademark streams and guides.

Unit 1 – Fluids

Explore Unit 2 of AP Physics 2 here! Things will heat up when you learn about thermodynamics, including thermal equilibrium, the ideal gas law, heat and energy transfer, contact forces, pressure, internal energy and energy transfer, elastic and inelastic collisions, conservation of momentum, and thermal equilibrium and entropy.

Unit 2 – Thermodynamics

Learn all about unit 3 in AP Physics 2 with our resources, and focus on electric force, field, and potential. The most important topics in this unit that our resources cover are electric systems, conservation of electric charge, electric forces, electric fields, and gravitational and electromagnetic forces.

Unit 3 – Electric Force, Field, & Potential

Study for the AP Physics 2 exam with our unit 4 resources and discover all about circuits. Electric charge, conservation of electric charge, resitivity and resistance, resistance and capacitance, and Kirchhoff's Loop Rule are just some of the things you'll learn about!

Unit 4 – Electric Circuits

Need to study for AP Physics 2? Use our unit 5 resources to master the topic of magnetism and electromagnetic induction! Key topics in unit 5 include electric fields and forces, magnetic fields, and electromagnetic induction.

Unit 5 – Magnetism & Electromagnetic Induction

Use our resources to review unit 6 in AP Physics 2! This unit covers geometric and physical optics. Teach yourself all about or brush up on electromagnetic waves, periodic waves, images from lenses and mirrors, interference and diffraction, and refraction, reflection, and absorption.

Unit 6 – Geometric & Physical Optics

Prepare for the AP Physics 2 exam with our unit 7 resources! This unit focuses on quantum, atomic, and nuclear physics, including systems and fundamental forces, radioactive decay, energy and modern physics, mass-energy equivalence, properties of waves and particles, and the photoelectric effect.

Unit 7 – Quantum, Atomic, & Nuclear Physics

Frequently Asked Questions

Exam Reviews

Prepare for the AP Physics 2 exam with our resources! They provide review of units, key concepts and topics, and exam strategies to help you do your best on exam day!

Big Reviews: Finals & Exam Prep

1.1 Fluid Systems

1.2 Density

1.3 Fluids: Pressure and Forces

1.4 Fluids and Free-Body Diagrams

1.5 Buoyancy

1.6 Conservation of Energy in Fluid Flow

1.7 Conservation of Mass Flow Rate in Fluids

Unit 1 Overview: Fluids

What are Fluids?

Object vs System

Fluid Systems

Density 🧊

Commonly Asked Questions About Density

Density

Pressure

What is Pressure?

Pascal's Principle

Pressure and Velocity: The Bernoulli Effect

Fluids: Pressure and Forces

Fluids and Free-Body Diagrams

What is Buoyancy?

Apparent Weight


Buoyancy

Conservation of Energy in Fluid Flow

Conservation of Mass Flow Rate in Fluids


Introduction

2.1 Thermodynamic Systems

2.2 Pressure, Thermal Equilibrium, and the Ideal Gas Law

2.3 Thermodynamics and Forces

2.4 Thermodynamics and Free-Body Diagrams

2.5 Thermodynamics and Contact Forces

2.6 Heat and Energy Transfer

2.7 Internal Energy and Energy Transfer

2.8 Thermodynamics and Elastic Collisions: Conservation of Momentum

2.9 Thermodynamics and Inelastic Collisions: Conservation of Momentum

2.10 Thermal Conductivity

2.11 Probability, Thermal Equilibrium, and Entropy

Unit 2 Overview: Thermodynamics

2.1 Thermodynamic Systems 💤 

What is Thermodynamics? 👀

Object vs. System

Thermodynamic Systems 💤 

Thermal Conductivity

Metals

Fourier's Conduction Law

Entropy

Heat Engines and Refrigerators

Probability, Thermal Equilibrium, and Entropy

Revisiting Pressure

Temperature and Kinetic Energy 🥵 

The Ideal Gas Law

Pressure, Thermal Equilibrium, and the Ideal Gas Law

Forces in Thermodynamics

Thermodynamics and Forces

Free-Body Diagrams

Author's suggestions for FBD

Forces

Thermodynamics and Free-Body Diagrams

What is Heat?

Heat Transfer Methods 

Heat and Energy Transfer

The 0th law 🌟 

The 1st Law 🌟 

Work 🔎

Signs ✏️

What is a PV diagram? 🧮

Internal Energy and Energy Transfer

Types of Collisions

Elastic Collisions

Thermodynamics and Elastic Collisions: Conservation of Momentum

Inelastic Collisions

Thermodynamics and Inelastic Collisions: Conservation of Momentum

3.1 Electric Systems


3.2 Forces and Potential Energy


3.3 Conservation of Electric Charge


3.4 Charge Distribution— Friction, Conduction, and Induction


3.5 Electric Permittivity


3.6 Introduction to Electric Forces


3.7 Electric Forces and Free-Body Diagrams


3.8 Describing Electric Force


3.9 Gravitational and Electromagnetic Forces


3.10 Vector and Scalar Fields


3.11 Electric Charges and Fields


3.12 Isolines and Electric Fields


3.13 Conservation of Electric Energy

Review Questions

Conclusion

Unit 3 Overview: Electric Force, Field, and Potential

Electric Systems 

Electric Systems 🔋

Vector and Scalar Fields

Scalar vs. Vector  💫

Vector Fields Snapshot

Scalar Fields Snapshot

Electric Charges and Fields

Electric Fields

Simple Fields

Electric Field Strength

Isolines and Electric Fields

Potential Difference (Electric Potential/Voltage)


Electric Potential of a Point Charge

Equipotential Lines

Conservation of Electric Energy

Electric Fields & Work

Hooke's Law

Conservative Forces

Gravitational Potential Energy

Forces and Potential Energy 

Conservation of Electric Charge 

CollegeBoard Essential Knowledge

Conductors and Insulators

Conservation of Electric Charge

How an Object Becomes Charged

Charge Distribution— Friction, Conduction, and Induction

Electric Permittivity 

Coulomb's Law Constant 

Permeability vs, Permittivity

Permittivity Values

Introduction to Electric Forces 

Newton's First Law

Newton's Second Law

Newton's Third Law

History and Introduction of Electric Forces

Introduction to Electric Forces

Electric Forces and Free-Body Diagrams

Electrostatic Force & Coulomb's Law

Free Body Diagrams (FBD)

Describing Electric Force

CollegeBoard Objectives:

Electric Force Basics

Force Interactions with Charges

Force Interactions with an Electric Field

Gravitational and Electromagnetic Forces

Electric vs Gravitational Force

4.0 Unit 4 Overview: Electric Circuits 

4.1 Definition and Conservation of Electric Charge 

4.2 Resistivity and Resistance 

4.3 Resistance and Capacitance 

4.4 Kirchhoff’s Loop Rule 

4.5 Kirchhoff’s Junction Rule and the Conservation of Electric Charge

Unit 4 Overview: Electric Circuits

Definition and Conservation of Electric Charge


Current 💨


Circuit Symbols & Measuring Tools 🛠️

Definition and Conservation of Electric Charge 

Resistivity and Resistance

Resistance 🛑

Resistors in Series & Parallel

Ohm's Law 💡

Power in Circuits

Non-Ideal Batteries and EMF 🚨

Resistance and Capacitance

What's a Capacitor?

Theory Time - Parallel Plate Capacitor 🎓

Energy in a Capacitor 💡

What Are Dielectrics?

Copy of Common Dielectrics

Why Does Adding a Dielectric Increase the Capacitance? 😕

Capacitors in Series & Parallel

Steady State Behavior 🎯

RC Circuits 🏍️

Kirchhoff’s Loop Rule

Types of Circuits (Series vs. Parallel)

Kirchhoff's Voltage Law (Loop Rule) ➿

Key Vocabulary

Kirchhoff's Junction Rule

The Conservation of Electric Charge

Application of Kirchhoff's Junction Rule and the Conservation of Electric Charge

2.5 Thermodynamics and Contact Forces

AP Physics 2 🧲

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