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Physics: explore STEM content (page 20 of 27) · openstem
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Physics
Mechanics, electromagnetism and quantum on openstem — flashcards, notes, quizzes, plots and sketches shared by the community. Study free, or clone anything into your library.
First law: energy bookkeeping Nothing is created or destroyed. The first law is conservation of energy with heat and work spelled out. Second law: heat picks a direction The first law alone would happily allow a cold object to warm a hot on
Physics
Physics · L3 · The Laws of Thermodynamics & Heat Engines
AHeat always flows from cold to hotBEnergy cannot be created or destroyed, only converted or transferredCEntropy always decreases over timeDAll engines are 100% efficient
Physics
Physics · L3 · The Laws of Thermodynamics & Heat Engines
Five quantities, four equations Straight line, constant acceleration. Five letters describe the whole motion. Each equation leaves one letter out. That's the feature, not a flaw. Choosing the right equation Three worked examples The braking
What a pendulum is Anything that hangs from a fixed point and is free to swing. A playground swing is one: you're the hanging weight, and the chains attach to a fixed bar above. Why it goes back and forth That's why it keeps going instead o
A chaotic system's sensitive dependence on initial conditions means that the separation δ(t) between two initially nearby trajectories grows:
ALinearly in time: δ(t) ∝ tBExponentially in time: δ(t) ∝ e^(λt), λ > 0CNot at all — chaotic trajectories stay close foreverDOnly in systems with explicit random noise added
One path, or many? A circuit is a loop from the battery and back. How the parts sit in that loop decides everything. Series: a single chain Parallel: separate branches Your house is wired in parallel. Unplugging a lamp shouldn't kill the fr
The bridge this note builds PV = nRT is a lab result. Kinetic theory derives it from molecules bouncing around, and in doing so tells you what temperature actually is. Pressure is just a lot of small collisions Model molecules as points bou
ABecause it keeps its own shape wherever you put itBBecause it takes the shape of its containerCBecause it spreads out to fill a roomDBecause you cannot see it