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

St. Peter's Colonnade

Building System

Arquitravat

Dimensions

15m high columns

Elements

Colonnade supporting an entablature surmounted by a balustrade and statues.

Interior Space

Bernini's design addressed several challenges:

1. Protocol: Accommodating a large number of pilgrims.
2. Topography: Working with uneven terrain.
3. Visibility: Creating a space that didn't obstruct the view of the basilica or surrounding palaces.
4. Focal Point: Integrating the Egyptian obelisk as the square's centerpiece.
5. Symbolism: Imbuing the square with significance as a symbol of the Church.

Bernini's solution involved a two-part design: two straight, slightly converging arms leading to an elliptical space centered around the obelisk and flanked by fountains. The portico comprises four... Continue reading "St. Peter's Colonnade: Architectural Masterpiece" »

Irradiance

This is the power emitted by the body per unit area and wavelength (W · nm^-1 • cm^-2). Furthermore, the irradiance of a lamp that is showing is similar to a black body.

Emissivity

It is the ratio of the irradiance of the lamp and a black body at the same temperature:

Emissivity (e, t) = I (lamp) (E, T) / I (black body) (E, T).

Gray Body

This occurs when the emissivity is independent of the wavelength of the lamp in question.

Deuterium Lamp

It is a low-pressure lamp that has a smooth continuum between 200 and 400 nm, and from this last value, the spectrum is more irregular with a large number of peaks. It also has a life of a few hundred hours. The QTH lamp (quartz-tungsten-halogen) issues more visible light than the Deuterium lamp in the... Continue reading "Spectrophotometry Basics" »

Average Speed

The average speed of a moving object is the ratio of the distance traveled along its path to the time taken.

Average speed = Δs / Δt

In vector calculus, the average velocity vector of a moving object is the ratio of its displacement vector to the time taken.

v = Δr / Δt

Instantaneous Velocity

The instantaneous velocity of a body is its velocity at a specific point in its trajectory. Its magnitude is called speed.

Acceleration

Acceleration measures how much the velocity of an object changes per unit time. Since velocity is a vector, changes can affect its magnitude, direction, or both.

Average Acceleration

The average acceleration of an object over a time interval is the change in its velocity divided by the time interval.

a = (v - v₀)... Continue reading "Understanding Kinematics: Speed, Velocity, and Acceleration" »

Diffraction Grating Experiment

Subject:

Calculate the d-spacing (d) of diffraction grating and determine wavelengths of different light sources.

Planning:

A diffraction grating is an optical component that separates light into its constituent wavelengths. There are two main types of diffraction gratings: reflection gratings and transmission gratings. A diffraction grating consists of a surface with a series of closely spaced parallel lines or slits. These can be etched onto a flat metal surface (reflection grating) or a glass plate (transmission grating). When monochromatic light (light of a single wavelength) is incident on a diffraction grating, the emerging waves interfere constructively at specific angles, resulting in a pattern of constructive... Continue reading "Diffraction Grating Experiment: Calculating Wavelengths" »

Content

Labor Force, Kinetic Energy, Potential Energy, Conservative and Nonconservative Forces, Power.

Development

Labor Force

A constant force produces work when applied to a body, it moves along a certain distance.
While work is done on the body, there is a transfer of energy to it, so it can be said that work is energy in motion. Moreover, if a constant force produces no movement, no work is done. For example, holding a book at arm's length does not involve any work on the book, regardless of effort. Work is expressed in Joules (J).

When the force is in the direction of motion:

L = Fd

L: Work done by force.

When the applied force has an inclination with respect to movement:

L = Fd cos θ

All the forces perpendicular... Continue reading "Work, Energy, and Power in Physics: Understanding the Basics" »

Surface Albedo and the Climate System

Albedo

Albedo is the ability of different surface types to reflect solar energy back into the atmosphere.

Radiation Balance

Radiation balance describes the energy flow converging in an area.

Key Threads:

• K: Solar radiation flux = S + D + K
• L: Terrestrial radiation flux = L_↑ + L_↓
• D: Sensible heat flux in the atmosphere
• H: Sensible heat flux in the soil
• C: Latent heat flux

Surface Radiative Balance

If T_s = 288 K (-15°C)

E_n = σT⁴ = 0.817 x 10^-10 Ly min^-1 K^-4 (288 K)⁴

E_n = 0.562 Ly min^-1 = 290 Kcal cm^-2 yr^-1

Since S = 1.94 Ly min^-1, the total energy intercepting the surface is:

SπR²

The total energy per unit area incident (Q₀) corresponding to 100% is:

Q₀ = SπR² / 4πR² = S / 4

Q₀ = 0.485 Ly min^-1 = 250 Kcal cm^-2 yr^-1

Ideal

Tensile Shots: Deformed Part Restoration Process

The process of restoring a deformed part using tensile shots involves basic traction equipment. The principle applied is a force equal to, but opposite in direction to, the deformation.

Straightening Equipment

Repairs are performed cold, using forces counter to the deformation. This equipment is capable of:

• Applying force at the appropriate point and direction.
• Properly anchoring the bodywork.
• Allowing for precise measurement.

Benches for Vehicle Repair

These include all elements and tools useful for diagnosing and repairing car structures affected by collisions. Measuring systems can be classified as: universal or positive control.

The choice of equipment is determined by work volume, vehicle models,... Continue reading "Automotive Body Repair: Straightening Techniques & Equipment" »

Uniform Rectilinear Motion (MRU)

An object performs Uniform Rectilinear Motion (MRU) if it travels equal distances in equal times and its trajectory is a straight line. The equation of motion allows us to determine the position of the body at every moment.

Uniformly Accelerated Rectilinear Motion (MRUA)

An object experiences Uniformly Accelerated Rectilinear Motion (MRUA) if its velocity changes by equal amounts in equal times, and its trajectory is a straight line.

Circular Motion (MC)

Circular Motion (MC) describes the path of an object along a circumference. For its study, the center of the circle is typically placed at the origin of the coordinate system. The following characteristics are always fulfilled:

• The magnitude of the position vector