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

Energy

Energy is the capacity of bodies to produce transformations in themselves or other bodies.

Energy Sources

Energy sources are natural resources from which humans can obtain usable energy.

Types of Energy Sources

• Non-renewable: Found in limited quantities and are depleted with use.
• Renewable: Considered inexhaustible as they are continuously renewed.

Energy Principles

• Conservation of Energy: The total energy in the universe remains constant in any process.
• Degradation Principle: With each transformation, energy loses quality and produces new transformations.

Work and Power

Work (W) is done when a constant force (F) is applied to a body, causing a displacement (d) in the same direction as the force: W = F * d.

Power is the rate at which work is done.... Continue reading "Energy, Waves, Sound, Light, and Electricity: Physics Fundamentals" »

Fundamental Concepts of Fluid Statics

Definition of Pressure

The Pressure (P) is defined as the ratio of the exerted Force (F) to the surface Area (S) over which it acts:

$$P = \frac{F}{S}$$

Hydrostatic Pressure

Hydrostatic Pressure is the pressure exerted by a liquid at all points within it.

Fundamental Equation of Fluid Statics

The pressure at a depth $h$ in a fluid of density $\rho$ under gravity $g$ is given by:

$$P = \rho g h$$

Communicating Vessels Principle

When several containers of different shapes containing the same liquid are connected at the bottom, the height of the liquid surface is identical in all vessels.

Application of Communicating Vessels

This principle is fundamental to water distribution systems for communities.

Determining Relative

Massage Session Protocol

1 - Abdomen (10 min)

• Making contact.
• Passes soft (Frictions).
• Venous Vaciaje.
• Friction palms circular (clockwise).
• Digital kneading.
• Frictions the entire colon (triangle).
• Venous Vaciaje.
• Palmar kneading (grasping).
• Pinching (roller technique).
• Click.
• Vibration on the solar plexus (hands alternating).
• Final Venous Vaciaje passes.

2 - Arms (3 min each)

• Rubbing in glove.
• Frictions.
• Simple knuckle kneading.
• Digital Roces (scratch with yolks).

Breast (1 min)

• Digital kneading the top.
• Circles around the breasts.

3 - Facial (5 min)

(Specific facial techniques would be listed here, content was empty.)

4 - Legs Supine (5 min per leg)

Ankle to Groin

• Palmar stroking (ankle to groin).

Thighs

• Palmar stroking (middle internal and external).
• Digital kneading

Kinematics and Motion Concepts

• Fri (Instantaneous Speed): The speed a moving body has at a specific point in its trajectory.
• Vm (Average Velocity): The quotient between displacement and the time interval used in traversing it.
• Am (Average Acceleration): The ratio between the variation of velocity experienced by the moving body at a given time interval.
• Ai (Instantaneous Acceleration): The acceleration that a moving body has at a given moment of the journey or at a point in its trajectory.
• Trajectory (Career): The line that connects all the points that the moving body has passed through during its displacement.
• Route Distance (E): The length of the path traveled.
• MCU (Uniform Circular Motion): A movement describing a moving body whose angular velocity

Quantum Theory: Transformacions: a) The photoelectric effect interpretacn dl was given earlier s.XX.Eisten x Eisten propagacn defends ql dl d s makes electroamgnetica Radia?Ná discreta.La justificacn l form is one Radia?Ná d cnd enregia E = hf collides cntra l d a metal surface and metal dl ls electrons absorb energy CNTS d h s f.Cnd this energy suficnt l ls electrons leave puedn metal, if not suficnt permanecn s metal.Esto nl ls kiere q DCIR enregetics exchanges will mean x producn d d CNTS energy and frequency depend dl dl ls radiacn.Tods metals are a function caracteriaza ql (dl function work w _L) Cnd l incidnt energy is higher than W _L, ls all absorbn metal d electrons enregia d ls l fotons adkiriend an EC max b) Argue if STET would produce

Position Vector and Components

The position vector r describes an object's location in space. Its components can be expressed in Cartesian or polar coordinates:

• Position Vector: r = xi + yj
• Cartesian X-component: x = r cos θ
• Cartesian Y-component: y = r sin θ
• Magnitude of Position Vector: r = √(x2 + y2)
• Angle of Position Vector: tan θ = y / x

Displacement

Displacement (Δr) is the change in an object's position:

• Final Displacement: Δr = rfinal - rinitial

Speed and Velocity

Speed is the magnitude of velocity. Velocity is a vector quantity describing the rate of change of position:

• Average Speed: vavg = Δr / Δt
• Instantaneous Speed: v = |dr / dt|
• Average Velocity: vavg = Δr / Δt
• Instantaneous Velocity: v = dr / dt

Acceleration

Acceleration (a) is the... Continue reading "Essential Kinematics Formulas and Motion Principles" »

Law of Gravitation

Every object in the universe that has mass exerts a gravitational attraction on other objects with mass, regardless of the distance between them. According to this law, more massive objects exert a greater force of attraction. In parallel, the closer objects are, the greater the force, following an inverse square law.

Considering two masses whose size is small compared with the distance that separates them, we can summarize this in an equation or law that states that the force exerted by a given object with mass m1 on one with mass m2 is directly proportional to the product of the masses and inversely proportional to the square of the distance between them.

A force is central where the position vector r is parallel to the force... Continue reading "Fundamental Physics Concepts Explained" »

Understanding Direct Current (DC)

Direct Current (DC) is the electric current flowing consistently in the same direction. The flow of current is determined by three interrelated quantities, the first being the potential difference across the circuit, often referred to as electromotive force or voltage.

Power Generators

A power generator consists of a rotating coil of wire inside a magnet. The magnet is known as the stator, while the rotating loop is called the rotor.

Classification of Generators

Generators are classified based on the currents they produce and their circuit configurations:

• Electromechanical generators
• Electrochemical generators
• Photovoltaic generators
• DC generators
• AC generators

Direction of Electric Current

When an external voltage source... Continue reading "Understanding Direct Current, Ohm's Law, and Electrical Resistance" »

44. (a) The Young’s modulus is given by

(b) Since the linear range of the curve extends to about 2.9 × 10⁸ N/m², this is approximately the yield strength for the material.

46. Since the force is (stress × area) and the displacement is (strain × length), we can write the work integral (eq. 7-32) as

  W =

  = A (differential strain)L  = AL (differential strain)

which means the work is  (wire-area) × (wire-length) × (graph-area-under-curve).  Since the area of a triangle (see the graph in the problem statement) is  (base)(height)  then we determine the work done to be

            W = (2.00 x 10^-6 m²)(0.800 m)(1.0 × 10^-3)(7.0 × 10⁷ N/m²) = 0.0560 J .

48. 46. Since the force is (stress × area) and the displacement is (strain... Continue reading "Young's Modulus and Material Strength Calculations" »

Understanding Energy Forms

• A circulating car: Kinetic energy.
• A shining light bulb: Thermal and light energy.
• A book on a library shelf: Potential energy.
• A cat chasing a mouse: Kinetic energy.

Kinetic Energy Calculation: Bullet Example

A bullet with a mass of 15 g moving at 50 m/s.

The formula for kinetic energy (Ec) is:

Ec = 1/2 * m * v2

Calculation:

Ec = 1/2 * 0.015 kg * (50 m/s)2 = 18.75 J

Potential Energy Calculation: Crane Example

The formula for gravitational potential energy (Ep) is:

Ep = m * g * h

Calculation for a 350 kg object lifted 7 m (assuming g = 10 m/s²):

Ep = 350 kg * 10 m/s2 * 7 m = 24,500 J

Energy Transformations in Action

Observe the following scenarios and identify who loses/gains energy and the types of energy involved:

• Launching an Arrow