Physics 01
Block on an Inclined Plane With Friction: How to Solve It
How to solve a block on an inclined plane with friction: the free-body diagram, weight components, normal force, whether it slides, and worked examples.
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Physics 02
How Long Does It Take to Fall From a Height?
Fall time and landing speed for drops from 1 m to 1 km, the one formula behind them, worked examples, and when air resistance starts to matter.
Physics 03
How to Write Numbers in Scientific Notation (With Steps)
Write any number in scientific notation: move the point, count the places, read the sign. Worked examples, E notation, engineering notation and multiplying.
Physics 04
Joules, Calories and kWh: Energy Units Explained
What a joule, a calorie, a food Calorie, a kilowatt hour, an electronvolt and a Btu are, the exact factors between them, and worked conversions.
Physics 05
Kinetic Energy vs Potential Energy: Examples With Numbers
Kinetic and potential energy worked through with real numbers: a skater, a roller coaster, a car at 50 and 100 km/h, a runner and the Moon.
Physics 06
Significant Figures Rules With Examples (and Why They Exist)
The significant figures rules with worked examples: which zeros count, how to round, and the different rules for multiplying and for adding.
Physics 07
SUVAT Equations Explained, With Worked Examples
The five SUVAT equations, how to pick the right one, where they come from, and four worked examples with real numbers, including two-answer cases.
Physics 08
What Is a Good Percent Error in a Physics Lab?
There is no single cut-off. How to judge a percent error against your uncertainty, with worked pendulum, speed of sound and specific heat examples.
Physics 09
Why Don't You Feel the Gravity of the Person Next to You?
Two people 1 m apart attract each other with 3.3 × 10⁻⁷ N. Here is the calculation, why Earth wins by a factor of two billion, and when the pull matters.