Tag
physics
26 entries tagged physics.
Physics & Space
Classical Mechanics
- Classical Mechanics: The MapPhysics becomes much easier once the formulas stop looking like unrelated tricks.
- Fluids: Pressure, Buoyancy, and FlowA fluid cannot sustain a static shear stress the way a rigid solid can. It deforms and flows.
- Forces and Newton's LawsKinematics says how motion changes. Dynamics asks why.
- From AP Physics 1 to Physics C Mechanics: What Calculus AddsAP Physics 1 and AP Physics C: Mechanics describe largely the same classical-mechanics world.
- Kinematics: Position, Velocity, and AccelerationKinematics describes motion without yet asking what causes it.
- Linear Momentum, Impulse, and CollisionsMomentum becomes especially powerful when forces are large, complicated, and short-lived — collisions, explosions, catches, impacts.
- Oscillations and Simple Harmonic MotionMany systems displaced from a stable equilibrium experience a force pushing them back toward it.
- Rotational Energy and Angular MomentumRotation has close analogues of the energy and momentum ideas used for translation.
- Torque and Rotational DynamicsA force can change an object's translational motion. But for an extended object, where the force acts also matters.
- Work, Energy, and PowerForce is a local description: what interaction acts right now?
Physics & Space
Electricity & Magnetism
- Capacitors and RC Circuits: Energy Storage Takes TimeA capacitor stores energy by separating opposite charges, creating an electric field between conductors. In the ideal two-terminal model the plates hold +Q and -Q; the device can remain neutral overall while storing energy.
- Current, Resistance, and Power: Where Electrical Energy GoesClosing a circuit does not send a fresh batch of electrons from a battery to a distant lamp at light speed. Mobile charges are already present in the wires. Changes in electromagnetic fields propagate through the circuit, establishing a drift motion whose speed is usually much smaller than the signal speed.
- DC Circuits: Kirchhoff’s Laws and Loaded SourcesA circuit drawing is a claim about connections, not a picture of physical wire positions. Two components are in parallel only if both ends connect to the same two nodes. They are in series only when the same current must pass through both, with no branching junction between them.
- Electric Fields: Charge, Superposition, and CancellationWhy can a neutral object respond to electricity, and why does zero total charge not imply zero field? The answer requires separating sources, fields, and the charge experiencing a force.
- Electric Flux and Gauss’s Law: When Symmetry Does the WorkGauss's law is always true for electric fields, but it is not always a shortcut for finding them. Its power comes from combining a global accounting rule with enough symmetry to determine a local field.
- Electric Potential: Turning a Field into an Energy LandscapeVoltage is not a stock of charge or a force. It is potential-energy difference per unit charge. This lets us translate the local force description into the energy accounting already familiar from mechanics.
- Electromagnetic Induction: Flux Change, Lenz’s Law, and EnergyA stationary magnet near a stationary wire does not continually generate current. What matters is a change in magnetic flux through a circuit, or motion that produces the equivalent electromechanical effect.
- Magnetic Fields and Forces: Bending Motion Without Doing WorkElectric fields can push a stationary charge. Magnetic force on a point charge depends on its motion. The combined classical Lorentz force is
Physics & Space
Physical Principles
- Chaos: Sensitive Dependence Without RandomnessIn ordinary speech, "chaos" means disorder.
- Double Pendulum: Two Simple Joints, Nonlinear MotionA simple pendulum already has nonlinear dynamics at large angles.
- EntropyEntropy is often introduced as “disorder,” but that metaphor fails surprisingly quickly. The more useful statistical idea is multiplicity: how many microscopic arrangements correspond to the same macroscopic state.
- Galileo Thermometer: Temperature Read Through BuoyancyA Galileo thermometer looks like a sealed glass column containing several floating glass bulbs, each carrying a temperature tag.
Physics & Space
Relativity
- Special RelativitySpecial relativity starts from two principles:
Physics & Space
Thermal Physics
- Entropy and Heat Engines: Why Conserved Energy Is Not All UsableThe statistical entropy entry explains why macrostates with many compatible microstates are overwhelmingly favored. Here the aim is operational: calculate entropy changes and use them to decide whether an energy-conserving machine is possible.
- Temperature, Heat, and the Ideal-Gas BridgeTemperature, heat, and internal energy answer different questions. Their separation is what allows thermal physics to extend mechanics rather than replace it.
- The First Law: Why the Path MattersEnergy conservation becomes thermodynamics when we specify a system boundary and distinguish energy transfer as heat from energy transfer as work. For a closed system with negligible changes in bulk kinetic and gravitational potential energy, use