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

Electric Field Fundamentals

5.a) Charged Particle Movement and Energy Changes

When a charged particle moves in an electric field, if the electric force (F_e) is conservative, the change in mechanical energy (ΔEM) is zero. This implies an inverse relationship between kinetic energy (Ec) and potential energy (Ep): if Ec increases, Ep decreases, and vice versa.

If a particle's speed decreases upon entering an electric field, its charge is negative. Conversely, if its speed increases, its charge is positive.

5.b) Work Done by Magnetic Fields on Charges

No work is performed by a magnetic field on a charged particle. A magnetic field generates a magnetic force that is always perpendicular to the path of the charged particle, meaning it does no work.

6.

Physics Concepts

Motion, Forces, and Laws

Motion

MUA
V = V₀ + a * t
D = |ee₀| = V₀ * t + 1/2 * a * t²

Forces

Sum of Concurrent Forces
F_R = √(F₁² + F₂² - 2 * F₁ * F₂ * cos(alpha))
Decomposition of Forces
F_x = F * cos(?)
F_y = F * sin(?)
Deformation (Hooke's Law)
L = l₀
F = K * Δl

Newton's Laws of Motion

1st Law (Inertia)
∑F = 0
2nd Law (Acceleration)
∑F = m * a
3rd Law (Action-Reaction)
For every action, there is an equal and opposite reaction.

Sum of Forces (Different Directions)

Concurrent Forces
R = √(F₁² + F₂²)
Parallel Forces
R = F₁ + F₂

Centripetal Force

F_c = m * a_n = m * v² / r = m * ω² * r

Other

P = m * g
F_r = μ * N

Force Interactions and Types

A force is an interaction between two bodies: the force exerted and the recipient.

• Weight: Gravitational force on

Direct Current (DC) Motor Components

DC Motor Constitution

• Stator (Carcass or Inductor)

  The fixed part, also known as the carcass or inductor. Its function is to create the excitation magnetic field. It may use permanent magnets or electromagnets (spools located around ferromagnetic poles). The protruding poles are typically made of soft iron casing and are not in parallel.

• Rotor (Induced or Armature)

  The moving part of the motor. Its primary function is to provide torque to move the shaft and generate a counter-electromotive force (EMF) that opposes the initial current intensity traveling through the coil. The rotor creates a magnetic field that opposes the inductor's magnetic field. It consists of the induced coil wound around a slotted ferromagnetic

Types of Waves

Mechanical Waves

These waves require a material medium for transmission. There are two main types:

• Longitudinal Waves: These waves travel parallel to the direction of propagation.
• Transverse Waves: These waves travel perpendicular to the direction of propagation, such as the waves on a vibrating guitar string.

Electromagnetic Waves

These waves do not require a physical medium for transmission.

Examples of Waves:

• Sound Waves: Acoustic waves.
• Seismic Waves: Caused by Earth's activity.
• Electromagnetic Waves: Related to electromagnetic forces.
• Wave Power: Generated by wind.
• Mechanical Waves: Produced by mechanical energy.
• Radio Waves: Propagate through the air.

Reflection of Light

The incident ray, the normal, and the reflected ray all lie in the... Continue reading "Light and Wave Phenomena" »

Metallography: The Science of Measurement

Metallography is the science that studies measurement, focusing on magnitudes like time, length, mass, and strength.

Units of measurement include SI and SA units. Instruments like rulers and calipers are used for measurement.

Specific rules ensure correct measurement, and proper instructions are necessary for using measuring instruments effectively.

Measurement Fundamentals

Measurement involves determining a numerical value for a quantity, such as length or mass.

Factors influencing measurement include the instrument's precision, the operator's skill, and environmental conditions.

Types of Measurement

• Direct Measurement: Obtaining a value immediately through instrument reading.
• Indirect Measurement: Requiring

Pressure and Fluids

What is Pressure?

Sometimes the effect of force also depends on the size of the surface on which it operates. The pressure takes into account two variables: the strength and the surface. Pressure occurs when a force acts on a unit area.

Pressure is defined as the force acting on a unit area (p = F / S). The SI unit is the newton per square meter (N/m²), which is called the pascal and whose symbol is Pa (1 Pa = 1N / 1 m²). Pressure is a scalar because it acts with an equal numerical value in all directions.

What are Fluids?

The term fluid includes both liquids and gases, and their properties are:

1. They do not have their own shape.
2. They take the form of the container that contains them.

This is because the particles that make up the... Continue reading "Understanding Fluid Pressure and Hydrostatics" »

The Vastness of Space: Galaxies, Stars, and Dark Matter

The universe is a vacuum containing billions of galaxies. In turn, each galaxy contains billions of stars, planets, and nebulae. In addition to visible objects, there is matter we cannot see: the so-called dark matter. Astronomers currently estimate that stars and planets occupy only 10% of the universe, while 90% is composed of dark matter.

Elemental Composition of the Cosmos

The universe is primarily made up of light elements:

• 75% Hydrogen
• 20% Helium
• 5% Other elements

This composition was determined by comparing the spectrum of white light with the spectrum of sunlight.

Defining a Galaxy

A galaxy is a massive cluster of stars, planets, gas, and dust. It typically has a supermassive black hole... Continue reading "Secrets of the Cosmos: Universe Composition and Formation" »

1. Strength and Equilibrium

The existing state of motion, or a body at rest, is defined by the forces acting upon it, which may deform or alter the state of that body.

2. Special Forces: Weight

The weight of a body on Earth is defined as the gravitational force of attraction.

3. Composition of Forces

The resultant force affecting a body is the vector sum of all individual forces acting upon it.

4. Decomposition of Forces

Sometimes, a force is resolved into two components. This operation, known as decomposition, results in the same impact on the body as the original force.

5. Equilibrium of Forces

A body is in equilibrium when the sum of two or more forces acting upon it is null, meaning the resultant force is zero.

6. Newton's Laws and Dynamics

Dynamics... Continue reading "Understanding Physics Dynamics: Newton's Laws and Force Principles" »

Types of Support and Channels

Wireless support's atmosphere is leading to it being transmitted through electromagnetic waves and sound. Wired support uses some sort of cable, such as coaxial cable or fiber optics.

Channels

Channels are real-time media communication that allows the same instant. Time media are those media differed in the signal sent by the sender is stored in any information recording system, such as magnetic tapes, CDs, and DVDs.

Codes

Communication codes are legion: the languages of mankind, color codes, writing, and language.

Parameters

• Amplitude: The maximum variation of the signal about the value zero.
• Period: The time lag between two consecutive steps by maximum wave value.
• Frequency: The number of oscillations that occur during

Swing Circuits and Electromagnetic Waves

To produce damped oscillations, circuits must be complex: and . Electromagnetic waves are composed of an electric field and a magnetic field (also known as Hertzian waves).

Wavelength and Dipole Antennas

Wavelength is the distance a wave travels during one complete cycle, calculated as λ = c / f. A dipole is a half-wavelength antenna consisting of two symmetrical conductors. In a half-wave dipole, the length between its ends coincides with half the wavelength of the target frequency.

Radiation Resistance and Polarization

Radiation resistance is the resistance of the dipole at resonance, typically 75Ω. The polarization radiation diagram defines the direction of the electric field of the electromagnetic... Continue reading "Fundamentals of Electromagnetic Waves and Satellite Systems" »