Notes, summaries, assignments, exams, and problems for Physics

Photons and Electrons in the Double Slit Experiment

Evidence for Wave-Particle Duality

• A single electron or photon leaves the source with particle-like discreteness and creates a single discrete spot on the screen.
• The interference pattern, which occurs over time, is a wave property.

Diffraction Pattern and Heisenberg’s Uncertainty Principle

• We cannot measure the exact position of each electron or its exact momentum as it approaches the slit; there is uncertainty in both position and momentum.
• The uncertainty in each electron’s y-position is reduced to the width of the slit (since we are certain it passes through the slit). This increases its uncertainty in the momentum of the y-direction.
• The uncertainty in the momentum in the y-direction means

Understanding Electrostatics

Electrostatics is the branch of physics that studies the phenomena produced by charges that do not vary or move.

History of Electrostatics

6th century BC: The Greeks discovered the electrical properties of amber. When rubbed, it could attract light objects.

18th century: Benjamin Franklin conducted experiments with different materials and observed that rubbed materials could either attract or repel each other.

Franklin's Theory of Electricity

• There are only two types of electricity: positive and negative.
• Electricity is a sort of fluid present in all objects and it can flow from one object to another by rubbing them.
• When there's an excess of electricity, objects have positive electricity, and when there's a lack of electricity,

Tower Bridge and the Historic Tower of London

Tower Bridge: Victorian Engineering Marvel

Tower Bridge, built in 1894, must be raised to enable tall ships to pass underneath. Until 1976, this operation was performed by steam-driven Victorian hydraulic machines. It is often mistakenly thought to be London Bridge by tourists.

Visitors can travel to the top of Tower Bridge and also see the historic Victorian Engine Room.

The Tower of London: A Millennium of History

The Tower of London (located across the river) is one of the most popular tourist attractions in London and one of the greatest examples of Norman architecture anywhere in the world.

It was begun by William I around 1066 and built deliberately just outside the city boundary to warn potential... Continue reading "London's Iconic Landmarks: Tower, Tate, St Paul's, and the Globe" »

Good morning today we are going to present the evolution of soccer balls.

Superball

The superball was a soccer ball that consisted of a chamber composed of a valve that prevented the air from coming out and a seam from outside to inside that was invisible and without a flange. This ball was the first ball made without tiento

Invention of the Invisible Tiento

In Bell Ville, in the Argentine province of Córdoba between 1929 and 1931 Romano Polo, Antonio Tossolini and Juan Valbonessi conducted numerous tests and trials that culminated in the invention of the ball with an invisible tiento, a ball that continued to be used for a couple of years.

Professional Use and Commemoration

The superball was first used professionally in the same year of its invention... Continue reading "Evolution of Soccer Balls: From Superball to Jabulani" »

Zaha Hadid was designing the BMW Central Building.

The eventuality described in the VP ‘design the BMW Central Building” is [-static, +durative, +telic], thus an accomplishment. As shown in this example, it is compatible with the progressive, which emphasizes the progress of a [+durative] eventuality. Three diagnostics can be used to show that this event is an accomplishment, not an activity:

1. It is compatible with in-PPs ('Zaha Hadid designed the BMW Central Building in three months.'), but not with for-PPs ('Zaha Hadid designed the BMW Central Building in three months').
2. It does not have the sub-interval property: A subinterval of the event described in ‘Zaha Hadid designed the BMW Central Building’ cannot be described as ‘Zaha Hadid

The Future of Physics

Science Fiction and Reality

Much of what we see in science fiction, such as time travel, warp drive, higher dimensions, portals through space and time, stargates, and wormholes, is actually within the realm of possibility according to the laws of physics.

Imagine meeting your grandparents in the year 1900, when they were simple farmers. Consider the powers of Greek gods: Zeus could control objects with his mind, materializing them at will. Venus possessed a perfect, ageless body. We are now beginning to understand the genetics of aging at the molecular level.

Apollo rode his chariot across the heavens. We will eventually have the flying cars we've always dreamed of. By the year 2100, we may have powers comparable to the gods.... Continue reading "The Power of Physics: From Aristotle to the Future" »

• Thermal energy is the energy that is exchanged between two bodies or systems of matter that have different temperatures. Thermal energy is also exchanged when a body changes from one physical state to another.

• Kinetic energy (Ec) is the energy of a body in motion. It depends on the mass and the speed of the body.

• Potential energy (Ep) is the energy of a body determined by its position. It depends on the body’s mass and position

• Gravitational Potential Energy
• Elastic potential energy

• Electrical energy is energy produced by the movement of charged particles (electrons), due to a potential difference.

• Radiant energy is energy carried by the electromagnetic waves, such as light, radio waves, microwaves, X-ray or γ rays. It’s called radiation. 

• Chemical

Relativity Law and Phenomena

The relativity law, analyzing phenomena for bodies whose speed is comparable to the speed of light

The time and the space can have a different reference system

Characteristics of Light

The light is reflected and has wave characteristics.

The measurement can be probabilistic and not precisely directs.

Measurement and Physical Magnitude

Measurement: the act of measuring as the comparison of a property or physical magnitude with another of the same class. Assigning a numerical value to the result of said measurement, and adding a unit of measurement which will give us an accurate idea of the physical magnitude that is being measured

Physical Magnitude: is the term associated with some property or characteristic measurable... Continue reading "Understanding Relativity and Measurement in Physics" »

Linear Kinetics

Law 1 of Inertia: object at rest and no external forces acting on it remains at rest, object in motion stays in motion, object at rest stays at rest, Law 2 of Acceleration: Change in motion is proportional to the force impressed and is made in direction of straight line. Force causes acceleration Law of Reaction: forces never act in isolation, but in pairs, forces equal to magnitude, in opposite direction. Conservation of Momentum: momentum before impact equals momentum after impact Impulse-momemtum: Ft=m(VF-VI) M=mv I=Ft

Torques & Moments

Torque: turnin effect produced by force aka moment, angular or rotary force, directly proportional to magnitude of force. Motion of a restrained system, force applied away from axis. Moment