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Topic 21
Why cepheids pulsate
Why cepheids pulsate
Click <a href="https://www.youtube.com/embed/X_3QAB3o4Vw?rel=0">https://www.youtube.com/embed/X_3QAB3o4Vw?rel=0</a> link to open resource.
Why cepheids pulsate
◄ Cepheid variables 1
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செய்திக் கருத்துக் களம்
Introduction to physics
Intro to vectors and scalars
Introduction to reference frames
Calculating average velocity or speed
Solving for time
Displacement from time and velocity example
Instantaneous speed and velocity
Position vs. time graphs
Acceleration
Airbus A380 take-off time
Airbus A380 take-off distance
Why distance is area under velocity-time line
Acceleration vs. time graphs
Average velocity for constant acceleration
Acceleration of aircraft carrier take-off
Airbus A380 take-off distance
Deriving displacement as a function of time, acceleration, and initial velocity
Plotting projectile displacement, acceleration, and velocity
Projectile height given time
Deriving max projectile displacement given time
Impact velocity from given height
Viewing g as the value of Earth's gravitational field near the surface
Choosing kinematic equations
Horizontally launched projectile
Visualizing vectors in 2 dimensions
Projectile at an angle
Total displacement for projectile
Launching and landing on different elevations
Total final velocity for projectile
Correction to total final velocity for projectile
Projectile on an incline
Unit vectors and engineering notation
Unit vector notation
Unit vector notation (part 2)
Projectile motion with ordered set notation
Newton's first law of motion introduction
More on Newton's first law of motion
Applying Newton's first law of motion
Newton's second law of motion
More on Newton's second law
Newton's third law of motion
More on Newton's third law
Normal force and contact force
Normal force in an elevator
More on Normal force (shoe on floor)
More on Normal force (shoe on wall)
Balanced and unbalanced forces
Unbalanced forces and motion
Slow sock on Lubricon VI
Normal forces on Lubricon VI
Inclined plane force components
Ice accelerating down an incline
Force of friction keeping the block stationary
Correction to force of friction keeping the block stationary
Force of friction keeping velocity constant
Intuition on static and kinetic friction comparisons
Static and kinetic friction example
Static and kinetic friction example
The force of tension
Mild and medium tension
Super hot tension
Introduction to tension
Introduction to tension (part 2)
Tension in an accelerating system and pie in the face
Treating systems (the hard way)
Treating systems (the easy way)
Two masses hanging from a pulley
Three box system problem
Masses on incline system problem
Race cars with constant speed around curve
Centripetal force and acceleration intuition
Visual understanding of centripetal acceleration formula
Optimal turns at Indianapolis Motor Speedway with JR Hildebrand
Calculus proof of centripetal acceleration formula
Loop de loop question
Loop de loop answer part 1
Loop de loop answer part 2
Centripetal force problem solving
Yo-yo in vertical circle example
Bowling ball in vertical loop
Mass swinging in a horizontal circle
Introduction to gravity
Mass and weight clarification
Gravity for astronauts in orbit
Would a brick or feather fall faster?
Acceleration due to gravity at the space station
Space station speed in orbit
Introduction to Newton's law of gravitation
Gravitation (part 2)
Introduction to work and energy
Work and energy (part 2)
Conservation of energy
Work and the work-energy principle
Work as the transfer of energy
Work example problems
Work as area under curve
Work/energy problem with friction
Conservative forces
Power
Intro to springs and Hooke's law
Potential energy stored in a spring
Spring potential energy example (mistake in math)
LOL diagrams
Vertical springs and energy conservation
Introduction to mechanical advantage
Mechanical advantage (part 2)
Mechanical advantage (part 3)
Introduction to momentum
Impulse and momentum dodgeball example
Bouncing fruit collision example
Bouncing fruit collision example
Momentum: Ice skater throws a ball
2-dimensional momentum problem
2-dimensional momentum problem (part 2)
Force vs. time graphs
Elastic and inelastic collisions
Solving elastic collision problems the hard way
Deriving the shortcut to solve elastic collision problems
How to use the shortcut for solving elastic collisions
Center of mass
Equation for center of mass
Angular motion variables
Relating angular and regular motion variables
Relationship between angular velocity and speed
Rotational kinematic formulas
Introduction to torque
Moments
Moments (part 2)
Finding torque for angled forces
Rotational version of Newton's second law
More on moment of inertia
Rotational kinetic energy
Rolling without slipping problems
Angular momentum
Constant angular momentum when no net torque
Angular momentum of an extended object
Ball hits rod angular momentum example
Cross product and torque
Intuition about simple harmonic oscillators
Definition of amplitude and period
Equation for simple harmonic oscillators
Period dependence for mass on spring
Phase constant
Pendulums
Introduction to harmonic motion
Harmonic motion part 2 (calculus)
Harmonic motion part 3 (no calculus)
Introduction to waves
Properties of periodic waves
The equation of a wave
Production of sound
Sound Properties: Amplitude, period, frequency, wavelength
Speed of Sound
Relative speed of sound in solids, liquids, and gases
Mach numbers
Decibel Scale
Why do sounds get softer
Ultrasound medical imaging
Doppler effect introduction
Doppler effect formula for observed frequency
Doppler effect formula when source is moving away
When the source and the wave move at the same velocity
Doppler effect for a moving observer
Doppler effect: reflection off a moving object
Wave interference
Constructive and Destructive interference
Standing waves on strings
Standing waves in open tubes
Standing waves in closed tubes
Beat frequency
Derivation of beat frequency formula
Specific gravity
Pressure and Pascal's principle (part 1)
Pressure and Pascal's principle (part 2)
Pressure at a depth in a fluid
Finding height of fluid in a barometer
Archimedes principle and buoyant force
Buoyant force example problems
Volume flow rate and equation of continuity
Bernoulli's equation (part 1)
Bernoulli's equation (part 2)
Bernoulli's equation (part 3)
Bernoulli's equation (part 4)
Bernoulli's example problem
Viscosity and Poiseuille flow
Turbulence at high velocities and Reynold's number
Venturi effect and Pitot tubes
Surface Tension and Adhesion
Thermodynamics part 1: Molecular theory of gases
Thermodynamics part 2: Ideal gas law
Thermodynamics part 3: Kelvin scale and Ideal gas law example
Thermodynamics part 3: Kelvin scale and Ideal gas law example
Thermodynamics part 5: Molar ideal gas law problem
Maxwell-Boltzmann distribution
Specific heat and latent heat of fusion and vaporization
Thermal conduction, convection, and radiation
Thermal conduction
Thermal conductivity of metal and wood
Intuition behind formula for thermal conductivity
Macrostates and microstates
Quasistatic and reversible processes
First law of thermodynamics / internal energy
More on internal energy
Work from expansion
PV-diagrams and expansion work
Proof: U = (3/2)PV or U = (3/2)nRT
Work done by isothermic process
Carnot cycle and Carnot engine
Proof: Volume ratios in a Carnot cycle
Proof: S (or entropy) is a valid state variable
Thermodynamic entropy definition clarification
Reconciling thermodynamic and state definitions of entropy
Entropy intuition
Maxwell's demon
More on entropy
Efficiency of a Carnot engine
Carnot efficiency 2: Reversing the cycle
Carnot efficiency 3: Proving that it is the most efficient
Triboelectric effect and charge
Coulomb's Law
Conductors and insulators
Conservation of charge
Electric field definition
Electric field direction
Magnitude of electric field created by a charge
Net electric field from multiple charges in 1D
Net electric field from multiple charges in 2D
Electric field
Proof: Field from infinite plate (part 1)
Proof: Field from infinite plate (part 2)
Electric potential energy
Electric potential energy (part 2-- involves calculus)
Voltage
Electric potential energy of charges
Electric potential at a point in space
Electric potential charge configuration
Introduction to circuits and Ohm's law
Resistors in series
Resistors in parallel
Example: Analyzing a more complex resistor circuit
Analyzing a resistor circuit with two batteries
Resistivity and conductivity
Kirchhoff's current law
Kirchhoff's voltage law
Electric power
Voltmeters and Ammeters
Electrolytic conductivity
Capacitors and capacitance
Capacitance
Energy of a capacitor
Capacitors in series
Capacitors in parallel
Dielectrics in capacitors
Introduction to magnetism
Magnetic force on a charge
Cross product 1
Cross product 2
Magnetic force on a proton example (part 1)
Magnetic force on a proton example (part 2)
Magnetic force on a current carrying wire
Magnetic force between two currents going in the same direction
Magnetic force between two currents going in opposite directions
Electric motors (part 1)
Electric motors (part 2)
Electric motors (part 3)
The dot product
Dot vs. cross product
Calculating dot and cross products with unit vector notation
Flux and magnetic flux
Faraday's Law Introduction
Lenz's Law
Faraday's Law example
Emf induced in rod traveling through magnetic field
Faraday's Law for generating electricity
Electromagnetic waves and the electromagnetic spectrum
Polarization of light, linear and circular
Constructive and Destructive interference
Young's double slit introduction
Young's double slit equation
Young's double slit problem solving
Diffraction grating
Single slit interference
More on single slit interference
Thin Film Interference part 1
Thin Film Interference part 2
Specular and diffuse reflection
Specular and diffuse reflection 2
Refraction and Snell's law
Refraction in water
Snell's law example 1
Snell's law example 2
Total internal reflection
Dispersion
Virtual image
Parabolic mirrors and real images
Parabolic mirrors 2
Convex parabolic mirrors
Derivation of the mirror equation
Mirror equation example problems
Convex lenses
Convex lens examples
Concave lenses
Object image and focal distance relationship (proof of formula)
Object image height and distance relationship
Thin lens equation and problem solving
Multiple lens systems
Diopters, Aberration, and the Human Eye
Light and the luminiferous ether
Potential ways to detect an ether wind
Michelson–Morley Experiment introduction
Starting to set up a Newtonian path–time diagram
Visualizing multiple Newtonian path–time diagrams
Galilean transformation and contradictions with light
Introduction to special relativity and Minkowski spacetime diagrams
Measuring time in meters in Minkowski spacetime
Angle of x' axis in Minkowski spacetime
Introduction to the Lorentz transformation
Evaluating a Lorentz transformation
Algebraically manipulating Lorentz transformation
Lorentz transformation derivation part 1
Deriving Lorentz transformation part 2
Lorentz transformation derivation part 3
Lorentz transformation for change in coordinates
Einstein velocity addition formula derivation
Applying Einstein velocity addition
Finding an in-between frame of reference
Calculating neutral velocity
Time dilation
Photon Energy
Photon Momentum
Photoelectric effect
De Broglie wavelength
Quantum Wavefunction
Quantum Wavefunction
Atomic Energy Levels
Bohr model radii
Bohr model radii (derivation using physics)
Bohr model energy levels (derivation using physics)
Bohr model energy levels
Absorption and emission
Emission spectrum of hydrogen
Heisenberg uncertainty principle
Quantum numbers
Quantum numbers for the first four shells
Mass defect and binding energy
Nuclear stability and nuclear equations
Types of decay
Writing nuclear equations for alpha, beta, and gamma decay
Half-life and carbon dating
Half-life plot
Exponential decay formula proof (can skip, involves calculus)
Introduction to exponential decay
More exponential decay examples
Exponential decay and semi-log plots
Discovery of magnetism
Compass: Which way is north?
Compass build (stroke direction)
Floating magnet
Compass build (magnet orientation)
Neutralize a compass
Compass interactions
Magnet near compass
Tracing a magnetic field
Discovery of magnetic fields
Magnetic permeability
Increase strength of magnet
Are 2 magnets stronger than 1?
Earth's magnetic field (how to measure)
Inverse cube law (deflection method)
Inverse cube law (method of oscillation)
Zinc copper cell (reduction-oxidation)
Battery meter (galvanometer)
Electrolyte test (pure water vs. vinegar)
Reverse electrodes (polarity)
Electrolyte (strong acid test)
Electrolyte (salt test)
Electrode (distance test)
Electrolyte (temperature test)
Electrode (surface area test)
Standard cell
How much electrolyte does a single cell need?
The battery and electromagnetism
Discovery of electromagnetism
Electromagnetic field (above vs. below)
Electromagnetic field (forward vs. reverse)
Electromagnetic field (loop)
AP Physics 1 review of 1D motion
AP Physics 1 review of 2D motion and vectors
AP Physics 1 review of Forces and Newton's Laws
AP Physics 1 review of Centripetal Forces
AP Physics 1 review of Energy and Work
AP Physics 1 review of Momentum and Impulse
AP Physics 1 review of Torque and Angular momentum
AP Physics 1 review of Waves and Harmonic motion
AP Physics 1 Review of Charge and Circuits
Question 1a: 2015 AP Physics 1 free response
Question 1b: 2015 AP Physics 1 free response
Question 1b: 2015 AP Physics 1 free response
Question 1c: 2015 AP Physics 1 free response
Question 2ab: 2015 AP Physics 1 free response
Question 2cd: 2015 AP Physics 1 free response
Question 3a: 2015 AP Physics 1 free response
Question 3b: 2015 AP Physics 1 free response
Question 3c: 2015 AP Physics 1 free response
Question 3c: 2015 AP Physics 1 free response
Question 3d: 2015 AP Physics 1 free response
Question 4: 2015 AP Physics 1 free response
Question 5: 2015 AP Physics 1 free response
Scale of the large
Scale of the small
Scale of earth and sun
Scale of solar system
Scale of distance to closest stars
Scale of the galaxy
Intergalactic scale
Hubble image of galaxies
Cosmological time scale 1
Cosmological time scale 2
Introduction to light
Four fundamental forces
Big bang introduction
Radius of observable universe
Radius of observable universe (correction)
Red shift
Cosmic background radiation
Cosmic background radiation 2
Hubble's law
A universe smaller than the observable
Birth of stars
Accreting mass due to gravity simulation
Becoming a red giant
White and black dwarfs
Star field and nebula images
Life cycle of massive stars
Supernova (supernovae)
Supernova clarification
Black holes
Supermassive black holes
Quasars
Quasar correction
Galactic collisions
Parallax in observing stars
Stellar parallax
Stellar distance using parallax
Stellar parallax clarification
Parsec definition
Cepheid variables 1
Why gravity gets so strong near dense objects
Plate tectonics: Difference between crust and lithosphere
Structure of the earth
Plate tectonics: Evidence of plate movement
Plate tectonics: Geological features of divergent plate boundaries
Plate tectonics: Geological features of convergent plate boundaries
Plates moving due to convection in mantle
Hawaiian islands formation
Pangaea
Compositional and mechanical layers of the earth
How we know about the earth's core
Seismic waves
Why S-waves only travel in solids
Refraction of seismic waves
The mohorovicic seismic discontinuity
Seasons aren't dictated by closeness to sun
How Earth's tilt causes seasons
Are southern hemisphere seasons more severe?
Milankovitch cycles precession and obliquity
Precession causing perihelion to happen later
What causes precession and other orbital changes
Apsidal precession (perihelion precession) and Milankovitch cycles
Intro to Moon phases
Solar and lunar eclipses
Why gravity gets so strong near dense objects ►
Home
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Course sections
General
One-dimensional motion
Intro to vectors and scalars
Topic 3
Topic 4
Topic 5
Topic 6
Topic 7
Topic 8
Fluids
Thermodynamics
Electric charge, field, and potential
Circuits
Magnetic forces, magnetic fields, and Faraday's law
Electromagnetic waves and interference
Geometric optics
Special relativity
Topic 17
Topic 18
Topic 19
Topic 20
Topic 21
Topic 22