Classical mechanics
Force, Mass, and Acceleration: How to Use Newton’s Second Law
Apply Newton's second law to net force with consistent SI units, a declared direction and a clearly defined system.
7 min readReviewed 2026-08-24
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Physics guides
Explore motion, forces, energy, electricity, waves, optics, and mechanics through clear models, units, diagrams, and worked examples.
Practical guides
Mechanical energy
Kinetic and Potential Energy: Calculate Mechanical Energy Correctly
Add translational kinetic and gravitational potential energy on one reference basis while keeping conservation assumptions and omitted energy transfers explicit.
7 min readReviewed 2026-08-24
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Electrical Power and Energy: Watts, Kilowatt-Hours, and Electricity Use
Calculate resistive DC power from voltage and resistance, then convert power over time to energy without confusing watts, joules and kilowatt-hours.
8 min readReviewed 2026-08-24
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