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| # Physics Knowledge Base | |
| ## Classical Mechanics | |
| ### Newton's Laws | |
| - **First Law**: An object remains at rest or in uniform motion unless acted upon by a net force | |
| - **Second Law**: F = ma (Force equals mass times acceleration) | |
| - **Third Law**: For every action, there is an equal and opposite reaction | |
| ### Kinematics | |
| - **Displacement**: Change in position of an object | |
| - **Velocity**: Rate of change of displacement (vector quantity) | |
| - **Acceleration**: Rate of change of velocity | |
| - **Equations of Motion**: v = u + at, s = ut + ½at², v² = u² + 2as | |
| ### Dynamics | |
| - **Force**: Push or pull that can change motion | |
| - **Weight**: Gravitational force on an object (W = mg) | |
| - **Friction**: Force opposing relative motion | |
| - **Tension**: Force transmitted through strings or cables | |
| ## Energy and Work | |
| ### Forms of Energy | |
| - **Kinetic Energy**: Energy of motion (KE = ½mv²) | |
| - **Potential Energy**: Stored energy due to position | |
| - **Gravitational PE**: PE = mgh (mass × gravity × height) | |
| - **Elastic PE**: Energy stored in deformed objects | |
| ### Work and Power | |
| - **Work**: Force × displacement in direction of force | |
| - **Power**: Rate of doing work (P = W/t) | |
| - **Efficiency**: Useful work output / total work input | |
| - **Conservation of Energy**: Energy cannot be created or destroyed | |
| ## Thermodynamics | |
| ### Laws of Thermodynamics | |
| - **Zeroth Law**: If two systems are in thermal equilibrium with a third, they are in equilibrium with each other | |
| - **First Law**: Energy cannot be created or destroyed (ΔU = Q - W) | |
| - **Second Law**: Entropy of an isolated system always increases | |
| - **Third Law**: Entropy approaches zero as temperature approaches absolute zero | |
| ### Heat and Temperature | |
| - **Temperature**: Measure of average kinetic energy | |
| - **Heat**: Energy transferred due to temperature difference | |
| - **Specific Heat**: Energy required to raise 1kg by 1°C | |
| - **Latent Heat**: Energy for phase changes without temperature change | |
| ## Waves and Oscillations | |
| ### Wave Properties | |
| - **Amplitude**: Maximum displacement from equilibrium | |
| - **Wavelength**: Distance between consecutive peaks | |
| - **Frequency**: Number of oscillations per second | |
| - **Period**: Time for one complete oscillation | |
| ### Types of Waves | |
| - **Transverse Waves**: Oscillations perpendicular to wave direction | |
| - **Longitudinal Waves**: Oscillations parallel to wave direction | |
| - **Standing Waves**: Waves that appear to stand still | |
| - **Resonance**: Amplitude increase at natural frequency | |
| ## Electricity and Magnetism | |
| ### Electric Charges | |
| - **Coulomb's Law**: F = k(q₁q₂)/r² | |
| - **Electric Field**: Force per unit charge | |
| - **Electric Potential**: Work per unit charge | |
| - **Capacitance**: Charge storage ability | |
| ### Electric Current | |
| - **Ohm's Law**: V = IR (Voltage = Current × Resistance) | |
| - **Power**: P = VI = I²R = V²/R | |
| - **Series Circuits**: Current same, voltage adds | |
| - **Parallel Circuits**: Voltage same, current adds | |
| ### Magnetism | |
| - **Magnetic Field**: Region where magnetic forces act | |
| - **Lorentz Force**: F = q(E + v×B) | |
| - **Faraday's Law**: Induced EMF proportional to rate of flux change | |
| - **Lenz's Law**: Induced current opposes flux change | |
| ## Modern Physics | |
| ### Quantum Mechanics | |
| - **Wave-Particle Duality**: Matter exhibits both wave and particle properties | |
| - **Heisenberg Uncertainty**: Cannot simultaneously know position and momentum exactly | |
| - **Quantum Tunneling**: Particles can pass through energy barriers | |
| - **Superposition**: Quantum systems can exist in multiple states simultaneously | |
| ### Relativity | |
| - **Special Relativity**: E = mc², time dilation, length contraction | |
| - **General Relativity**: Gravity as curvature of spacetime | |
| - **Mass-Energy Equivalence**: Mass and energy are interchangeable | |
| - **Spacetime**: Four-dimensional fabric of universe | |
| ## Optics | |
| ### Light Properties | |
| - **Reflection**: Light bouncing off surfaces | |
| - **Refraction**: Light bending when changing medium | |
| - **Diffraction**: Light bending around obstacles | |
| - **Interference**: Light waves combining constructively or destructively | |
| ### Lenses and Mirrors | |
| - **Convex Lens**: Converges light rays | |
| - **Concave Lens**: Diverges light rays | |
| - **Focal Length**: Distance from lens to focal point | |
| - **Magnification**: Ratio of image to object size | |