Physics I: Classical Mechanics
Video Lectures
Displaying all 35 video lectures.
I. Kinematics | |
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Lecture 1 Play Video |
Measurements of Space and Time This lecture is about units, dimensions, measurements and associated uncertainties, dimensional analysis, and scaling arguments. |
Lecture 2 Play Video |
Speed, Velocity and Acceleration This lecture is an introduction to kinematics which ultimately leads (in Lecture 4) to trajectories in 3 dimensions. |
Lecture 3 Play Video |
Vectors This lecture is about units, dimensions, measurements and associated uncertainties, dimensional analysis, and scaling arguments. |
Lecture 4 Play Video |
3D Kinematics: The Motion of Projectiles In this video lecture, Prof. Walter Lewin lectures about motion of projectiles (if air drag can be ignored). The objects experience a constant vertical acceleration due to the acceleration of gravity (see also Lecture 12). |
Lecture 5 Play Video |
Circular Motion In this video lecture, Prof. Walter Lewin teaches about circular motion, centrifuges moving, reference frames and perceived gravity. |
Lecture 6 Play Video |
Newton's Three Laws In this video lecture, Prof. Walter Lewin lectures on Newton's First (inertia), Second (F=ma) and Third (action=-reaction) Laws. |
Lecture 7 Play Video |
Weight and Weightlessness In this video lecture, Prof. Walter Lewin explores weight, perceived gravity, weightlessness, free fall, zero perceived gravity in orbit. |
Lecture 8 Play Video |
Frictional Forces In this video lecture, Prof. Walter Lewin lectures exclusively with frictional forces. |
Lecture 9 Play Video |
Exam Review In this video lecture, Prof. Walter Lewin reviews selected topics previously covered in lectures 1 through 5. |
Lecture 10 Play Video |
Hooke's Law and Simple Harmonic Motion In this video lecture, Prof. Walter Lewin begins his lecture covering topics like the restoring force of a spring (Hooke's Law) which leads to an equation of motion that is characteristic of a simple harmonic oscillator (SHO). Using the small angle approximation, a similar expression is reached for a pendulum. |
II. Work and Energy | |
Lecture 11 Play Video |
Work and Mechanical Energy In this video lecture, Prof. Walter Lewin introduces concepts such as work, conservative forces, potential energy, kinetic energy, mechanical energy and Newton's law of universal gravitation. |
Lecture 12 Play Video |
Resistive Forces In this video lecture, Prof. Walter Lewin lectures on resistive forces such as air drag. It includes the viscous (linear in velocity) and pressure (quadratic in velocity) terms. Quantitative demonstrations with balloons and with ball bearings dropped in syrup are shown. |
Lecture 13 Play Video |
Conservative Forces and SHO In this video lecture, Prof. Walter Lewin lectures on the conservation of mechanical energy which can be used to derive the equation of motion for simple harmonic oscillators (SHO). |
Lecture 14 Play Video |
Energy, Power and Satellite Orbits In this video lecture, Prof. Walter Lewin lectures on bound and unbound orbits; escape velocity. Various sources of energy, energy storage, energy conversion, and the world's energy consumption are also discussed. |
III. Momentum | |
Lecture 15 Play Video |
Collisions and the Center of Mass In this video lecture, Prof. Walter Lewin introduces momentum and its conservation during collisions. Kinetic energy can decrease or increase during collisions. When kinetic energy is conserved, we call it an elastic collision. |
Lecture 16 Play Video |
Elastic and Inelastic Collisions In this video lecture, Prof. Walter Lewin discusses 1D Elastic Collisions, Brain Teasers, Elastic Collisions with a Wall, Center of Mass (CM), Frame of Reference, 1D Inelastic Collision, Internal Energy and a demonstration of Newton's Cradle. |
Lecture 17 Play Video |
Change of Momentum, Impulse and Rockets In this video lecture, Prof. Walter Lewin lectures on the momentum of individual objects which change in a variety of ways. |
Lecture 18 Play Video |
Exam Review In this video lecture, Prof. Walter Lewin gives an exam review. |
IV. Celestial Mechanics | |
Lecture 19 Play Video |
Rotational Kinetic Energy In this video lecture, Prof. Walter Lewin lectures on Rotating Rigid Bodies, Moments of Inertia, Parallel Axis and Perpendicular Axis Theorem. The moment of inertia for a rigid body around an axis of rotation is introduced, and related to its rotational kinetic energy. Flywheels can be used to store energy. Planets and stars have spin rotational kinetic energy, and the Crab Nebula pulsar is presented as a spectacular example. |
Lecture 20 Play Video |
Angular Momentum In this video lecture, Prof. Walter Lewin introduces Angular momentum (a vector). The rate of change of angular momentum is related to the torque (also a vector). In the absence of an external torque, angular momentum is conserved. Spin angular momentum (of planets, stars, neutron stars) is also discussed. |
Lecture 21 Play Video |
Torques and Oscillating Bodies In this video lecture, Prof. Walter Lewin discusses how in the absence of a net external torque on an object, angular momentum is conserved. He also discusses when an object oscillates about an axis of rotation, and how there is a variable restoring torque acting on the object. |
Lecture 22 Play Video |
Kepler's Laws and Elliptical Orbits In this video lecture, Prof. Walter Lewin lectures on Kepler's Laws, Elliptical Orbits, Change of Orbits, and the famous passing of a Ham Sandwich. Kepler's three Laws summarize the motion of the planets in our solar system. Following Newton's law of universal gravitation, the conservation of angular momentum and mechanical energy allow us to calculate the semimajor axis of the elliptical orbits, the orbital period and other orbital parameters. All we have to know is one position and the associated velocity of a planet and the entire orbit follows. |
Lecture 23 Play Video |
Doppler Shift and Stellar Dynamics In this video lecture, Prof. Walter Lewin lectures on the Doppler Effect, Binary Stars, Neutron Stars and Black Holes. Doppler shift is introduced with sound waves, then extended to electromagnetic waves (radiation). The Doppler shift of stellar spectral lines and/or pulsar frequencies provides a measure of the line-of-sight (so-called radial) velocity of the source relative to the observer. Combined with Newton's law of universal gravitation, this can lead to the orbital parameters and the mass of both stars in a binary star system. |
Lecture 24 Play Video |
Rolling Motion & Gyroscopes In this video lecture, Prof. Walter Lewin lectures on Rolling Motion and Gyroscopes. This material is Very Non-intuitive. |
V. Solid Mechanics | |
Lecture 25 Play Video |
Static Equilibrium In this video lecture, Prof. Walter Lewin lectures on Static Equilibrium, Stability and Rope Walkers. Static equilibrium is only achieved when the net external force AND net external torque on an object are both zero. |
Lecture 26 Play Video |
Elasticity of Materials In this video lecture, Prof. Walter Lewin discusses Elasticity and Young's Modulus. The fractional length deformation of a material (the strain) depends on the force per unit area (the stress). The stress vs. strain dependence is described conceptually, then explored empirically. |
VI. Fluid Mechanics | |
Lecture 27 Play Video |
Pressure in a Static Fluid In this video lecture, Prof. Walter Lewin discusses concepts such as gases and incompressible liquids, Pascal's Principle, hydrostatic and barometric pressure. |
Lecture 28 Play Video |
Buoyant Force and Bernoulli's Equation In this video lecture, Prof. Walter Lewin discusses concepts such as Hydrostatics, Archimedes' Principle, Fluid Dynamics, factors which make a boat float, and Bernoulli's Equation. |
Lecture 29 Play Video |
Exam Review In this video lecture, Prof. Walter Lewin reviews selected concepts previously covered in lectures 16 through 24. |
Lecture 30 Play Video |
Other Oscillating Systems In this video lecture, Prof. Walter Lewin lectures on the simple harmonic oscillations (SHO) of suspended solid bodies which are related to their geometry. He also discusses how torsional pendulum oscillates in the horizontal plane, and the SHO does NOT depend on the small angle approximation. |
Lecture 31 Play Video |
Forced Oscillations and Resonance In this video lecture, Prof. Walter Lewin lectures on systems consisting of pendulums and springs and how they can freely oscillate at their natural frequencies (also called normal modes). He also discusses when we expose a system to a wide spectrum of frequencies, the response will be very large at the normal mode frequencies (resonances) of that system. Examples include musical instruments (standing waves on violin strings and pressure waves in wind instruments), and torsional standing waves on a bridge driven by strong winds. |
VII. Thermal Physics | |
Lecture 32 Play Video |
Heat, Conductivity and Thermal Expansion In this video lecture, Prof. Walter Lewin discusses how heat raises the temperature, and usually the volume of the material that absorbs the heat. He also lectures on the linear and cubical thermal expansion coefficients of metals (including mercury), which are described and demonstrated. Ice is also discussed as a special case. |
Lecture 33 Play Video |
Kinetic Gas Theory & Phases In this video lecture, Prof. Walter Lewin introduces the ideal-gas law and the rate of momentum transfer from the gas molecules to the vessel walls, which is related to pressure. The concepts of phase diagrams and phase transitions are also introduced, and they are explored with fire extinguishers, boiling water, and cooled balloons filled with air. The ideal-gas law holds (approximately) when you have only gas; it doesn't hold whenever there is any liquid present. |
VIII. Modern Physics | |
Lecture 34 Play Video |
The Wonderful Quantum World In this video lecture, Prof. Walter Lewin discusses Classical Mechanics, and in spite of all of its impressive predictive power, fails to explain many microscopic behaviors. This led to the development of Quantum Mechanics, where electrons orbit nuclei in discrete energy levels, light can behave as a particle, and particles behave as waves. The location of microscopic particles can only be expressed in terms of probabilities. Heisenberg's uncertainty principle is also discussed and demonstrated. |
Lecture 35 Play Video |
X-ray Astronomy and Astrophysics In this video lecture, Prof. Walter Lewin talks about some of the highlights from his early days at MIT. It began with balloon flights at very high altitude to make observations of the stars in X-rays. This led to discoveries of X-ray flaring events and a periodic X-ray source (GX 1+4). In the seventies and eighties he made important contributions to our understanding of X-ray bursts (thermo-nuclear fusion episodes on neutron stars). |