## Cheat Sheet

# Physics I Workbook For Dummies

Avoid difficulties when working on physics by knowing the common issues that can cause trouble in physics problems, understanding physical constants, and grasping principal physics equations.

## 10 Issues to Avoid When Solving Physics Problems

If you get stumped working on physics formulas, take a deep breath, and recheck your work. Go through these common physics-problem issues to make sure you have avoided them:

Mixing units

Expressing the answer in the wrong units

Swapping radians and degrees

Getting sines and cosines mixed up

Failing to treat vectors as vectors

Neglecting latent heat

Getting refraction angles wrong

Getting the signs wrong in Kirchhoff's loops

Adding resistors incorrectly

Getting ray diagrams wrong

## 9 Physics Constants to Know

Physics constants, like the mass of a proton or speed of light, are physical quantities with fixed numerical values. This list contains the most common physics constants:

Avogadro's Number: N

_{A}= 6.022 × 10^{23}mol^{–1}Boltzmann's constant: k = 1.380 × 10

^{–23}J/KCoulomb's constant: k = 8.99 × 10

^{9}N–m^{2}/C^{2}Gas constant: R = 8.314 J/(mol–K)

Gravitational constant: G = 6.672 × 10

^{–11}N–m^{2}/kg^{2}Speed of light: c = 2.997 × 10

^{8}m/sCharge of electron: e = 1.602 × 10

^{–19}CMass of proton: m

_{p}= 1.672 × 10^{–27}kgMass of electron: m

_{e}= 9.109 × 10^{–31}kg

## Important Physics Equations to Remember

Physics is packed with formulas and equations. This comprehensive list, arranged by topic, represents essential physics equations you need to keep handy when you're dealing with physics formulas.