Frequently Asked Questions
What conditions do these formulas assume?
Physics formulas typically assume idealized conditions: no air resistance (unless explicitly included), point masses, uniform fields, and constant material properties. Real-world systems deviate from these ideals. Results are exact under the stated assumptions but may need correction factors for engineering applications where deviations are significant.
How do I verify this result experimentally?
Design a simple experiment that measures the quantity your calculation predicts. Compare your measured value to the calculated value — a difference within measurement uncertainty confirms the formula applies to your situation. Systematic differences suggest a missing factor (e.g., friction, thermal expansion) that the basic formula doesn't account for.
What are significant figures in physics?
Express your result to the same number of significant figures as your least precise input. If you measure a length to ±1mm, don't report a result to ±0.001mm — the extra precision is false. In physics, misrepresented precision is considered an error in itself. For engineering tolerances, always round to the conservative (larger) side.
When does classical physics break down?
Classical (Newtonian) mechanics breaks down at very high speeds (near the speed of light, where special relativity applies), very small scales (subatomic, where quantum mechanics applies), and near massive objects (where general relativity applies). For everyday scales — from millimeters to kilometers, from micrograms to millions of kilograms — classical formulas are accurate to many decimal places.