In the first part, we discussed the idea of a functional, what it means, and how to find its extrema using the calculus of variations. However, those equations don’t really capture how amazing and applicable calculus of variations really is so the following will be some examples of this. In fact, the drawn out results from the posts The Shape of a String and The Lagrangian are just two cases of the one equation.

# Category: Physics

# Jumping in the Earth

This is just a quick fun article that may be trivial to some readers but will probably be very interesting to others. Imagine you jump through a hole that goes through the center of the earth like the little man below. Read More »

# General Relativity

General Relativity is perhaps one of the most enlightening theories in all of physics that reconciles many fundamental ideas about gravity, mass, and spacetime. The understanding of such a theory requires, in some sense, a certain conceptual jump which in the past has been explained through a “stretchy fabric” where mass acts as wells and other masses fall into these wells acting as a conceptual picture of general relativity. If you don’t know what I’m talking about, watch this video. This is immensely flawed in many ways. Read More »

# Heisenberg Uncertainty Derivation

The Heisenberg uncertainty principle seems like a principle that is so fundamentally experimental but it can actually be derived through theory. This requires the consideration of three concepts: the Cauchy-Shwarz inequality, measurement operators, and commutators.Read More »

# Quantum Teleportation

Quantum teleportation is the idea that entangling states can cause very fast information transfer. The name however is misleading as this information transfer is not instantaneous but simply travels at the speed of light. The basis of this idea is based on a very interesting trick that arises out of some of the math of quantum computing.Read More »

# Speed of Light Derivation

The speed of light may seem like an arbitrary constant of nature but, in some sense, it is actually set by other properties of the world. These other properties are the strengths of the electric and magnetic fields which are defined by the constants that are used in determination of them, otherwise known as the permittivity constant () and permeability constant (). Because light is simply an electromagnetic wave, one can derive its speed using these constants.Read More »

# Complex Impedance

There is a certain luxury of circuit calculations for systems contain direct current that alternating current systems really do not have. It is the idea that voltage and current are “synced.” An increase in voltage will create a corresponding increase in current seemingly instantaneously. However, an alternating current that experiences voltage oscillations experiences a delay. This can mean voltage is at the highest point in its fluctuations while current only reaches such a point a little bit later at which point voltage might already be at its lowest. The ratio of voltage to current is also unclear in these circuits. This makes it hard to describe the system easily.Read More »

# On Conservation

Conservation of different properties in nature immensely simplifies calculations to the point where some are impossible without the consideration of them. In some cases, it seems completely intuitive and impossible not to consider. However, not only are there many conservations laws unknown to many but there are also, in some sense, “violations” to these laws.Read More »

# The Shape of a String

Holding a string up with both ends at the same elevation causes the string to form a curve which not many really care to look into more than the first glance. At first, one may just assume that it is a parabola but upon closer look, it actually has a very interesting mathematical shape which is shown below.Read More »

# Strong Force and Nuclear Binding Energies

Forces come in various forms in nature but the nature of the strong force is very peculiar in that it does not create an attraction or repulsion between any two entities. It uses mass energy as a way to create a potential energy well. This is done by the following.Read More »