Physics I Workbook For Dummies Cheat Sheet

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 the Direction of Forces Wrong

• Getting the signs wrong in Kirchhoff’s loops
• Adding resistors incorrectly

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 × 10²³ mol^–1

• Boltzmann’s constant: k = 1.380 × 10^–23 J/K

• Coulomb’s constant: k = 8.99 × 10⁹ N–m²/C²

• Gas constant: R = 8.314 J/(mol–K)

• Gravitational constant: G = 6.672 × 10^–11 N–m²/kg²

• Speed of light: c = 2.997 × 10⁸ m/s

• Charge of electron: e = 1.602 × 10^–19 C

• Mass of proton: m_p = 1.672 × 10^–27 kg

• Mass 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.