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

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" »

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

Acoustics and Noise Principles

1. What is sound, from a technical perspective?

Answer: Sound is a mechanical vibration of a physical medium. It is a longitudinal wave that travels through the air.

2. When addressing a noise problem, what measures can be taken? Explain clearly.

Answer: Isolate the source with a solid, low-density material.

3. My neighbor's stereo is at 40 dB:

Answer: Chilean law considers a maximum of 45 dB between 9 PM (21:00 hrs) and 7 AM (07:00 hrs). Therefore, a personal solution would involve covering my ears or isolating my room.

4. A sound pressure measured in atmospheres is 2 atm. Calculate the noise intensity and discuss the obtained value.

5. Name three standards that can be referenced to solve a neighborhood noise problem:

Understanding Light: Key Optical Concepts

Index of Refraction

We define the index of refraction (n) of a medium as the ratio between the speed of light in a vacuum (c) and the speed of light in that medium (v):

n = c / v

Laws of Reflection of Light

When light rays strike a surface, they undergo a rebound that follows these laws:

1. The incident ray, the normal to the surface, and the reflected ray all lie in the same plane.
2. The angle of incidence (i) is equal to the angle of reflection (r), and they are on opposite sides of the normal: i = r.

Laws of Refraction of Light

When light passes from one transparent medium to another where the speed of light changes, its direction also changes. This phenomenon is known as the refraction of light, governed by these... Continue reading "Fundamentals of Light: Reflection, Refraction, and Lenses" »

Definitions AC. The changing of direction.
CURRENT. The meaning does not change, but may change in value. CURRENT PERIODIC. That which is repeated in cycles with the same period. PERIOD. Time it takes one cycle. CYCLE. Set starting values such that at any one walking back to the all the values of the signal. FREQUENCY. Number of cycles a second. The unit hertz. Resonance frequency is that frequency that makes a circuit is resistive (the circuit contains inductors and capacitors). Or half-power frequency cut-off frequency filter. That often happens in these situations simultaneously: the power half the maximum, the load voltage is 70% of the maximum, the phase angle is 45 degrees. BANDWIDTH. Difference between the cutoff frequencies. OR QUALITY

Fundamental Concepts in Fluid Mechanics

Pressure and Phase Changes

• Evaporation: The constant movement of molecules on the surface of a liquid, allowing them to escape into the atmosphere.
• Boiling: Occurs when the pressure to which a liquid is subjected equals its vapor pressure.
• Vapor Pressure: The partial pressure exerted by molecules in the gaseous state within a container when occupying a space above a liquid.
• Saturation Pressure: The state where there is a dynamic balance between the number of molecules that evaporate and condense.
• Cavitation: A phenomenon where, if the local pressure (p) in a liquid drops to or below its vapor pressure, the liquid rapidly evaporates, forming vapor bubbles. These bubbles then move and collapse violently within