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

Gauss's Law in Electromagnetism

For a closed surface represented by i, the number of electric field lines leaving the surface is equal to the number of lines entering it. This is consistent with the fact that no net charge is enclosed by the surface. However, for the closed surface ii in the same figure, there is a net outward flux, indicating a net positive charge enclosed.

The situation is radically different for magnetic fields, which are continuous and form closed loops. Examine the Gaussian surfaces represented by i or ii. Both cases visually demonstrate that the number of magnetic field lines leaving the surface is balanced by the number of lines entering it. The net magnetic flux is zero for both surfaces. This is true for any closed surface.... Continue reading "Electromagnetic Principles: Flux, Induction, and AC Power Generation" »

EQUATIONS

EMF and Potential Difference

Resistance

CURRENT

POTENTIAL DIFFERENCE (P.D.)

RESISTANCE

OHMIC CONDUCTORS

Understanding Motion and Forces

Acceleration Defined

Acceleration occurs when unbalanced forces cause a change in motion. It is directly related to the size and direction of the applied force. An object accelerates in the same direction it is pushed or pulled. Greater force results in greater acceleration.

Acceleration is inversely related to an object's mass; a large mass results in small acceleration for a given force.

Newton's Second Law of Motion

Newton's Second Law states that the acceleration of an object is directly proportional to the net force acting upon it and inversely proportional to its mass.

Understanding Weight and Units

Weight is a force, calculated as mass multiplied by the acceleration due to gravity (w = m ⋅ g).

Key Physics Units

• Force

Understanding Pendulums

State the following terms:

• Pendulum
• Simple pendulum
• Conical pendulum

Ans: A tiny mass (assumed to be a point object and called a bob) connected to a long, flexible, massless, inextensible string, and suspended to a rigid support is called a pendulum.

If a tiny mass (assumed to be a point object and called a bob) connected to a long, flexible, massless, inextensible string, and suspended to a rigid support is made to oscillate in a single vertical plane, it is said to be a simple pendulum.

A tiny mass (assumed to be a point object and called a bob) connected to a long, flexible, massless, inextensible string, and suspended to a rigid support revolves in such a way that the string moves along the surface of a right circular cone... Continue reading "Understanding Pendulums, Fluid Pressure, and Molecular Forces" »

Measurement of Pressure Losses in Pipes

1. Measurement of pressure losses in pipes under pressure can be made with: Piezometers

Flow Number and Linear Losses Factor

2. The flow number a is expressed in units: This value is dimensionless.

3. The linear losses factor f can be determined on the basis of: Relative roughness and Reynolds Number.

Orifice and Pump Head

4. The ISA orifice can be used to measure: Flow rate.

5. The pump head can be determined from: Bernoulli equation.

Absolute Roughness and Outlet Pressure

7. Absolute roughness can be determined: From Colebrook-White's formula.

8. The outlet pressure in the nozzle depends on: Flow rate in the nozzle.

Hydrostatic Pressure and Force

9. The unit of hydrostatic pressure in the SI system: kg/(m*s^2)

10.

Q4) The most widely used equation for estimating visibility is the Koschmeider equation:

                              Lv = 1200 km x µg/m³ / particle concentration

Where Lv is the visual range, the distance at which an average person can barely distinguish a dark object (such as a mountain or skyscraper) against the sky. This equation is an approximation, based on an average set of atmospheric particles.

• In the Grand Canyon and the surrounding area, on clear days, one can easily see mountains 120 miles away. What is the probable concentration of particles in the atmosphere when one can see that far?
• If the particle concentration in the atmosphere is increased by 1.5 µg/m³, what is the percentage decrease in the visual

Verb Alternations in English

The body-part possessor ascension alternation is characterized by a change in the expression of a possessed body part. The possessed body part may be expressed as the direct object of the verb (e.g., Margaret cut Bill’s arm), or the possessor may be expressed as the object of the verb with the possessed body part expressed in a prepositional phrase (e.g., Margaret cut Bill on the arm).

Examples:

• NPagent Verb [NP’s body-part]theme: Margaret cut [Bill’s arm].
• B-p possessor ascension construction: NPagent Verb [NPtheme] [on the body-part]: Margaret cut [Bill] [on the arm].

The body-part possessor ascension requires a sub-event ACT that involves contact. Consequently, "break" verbs typically do not participate in this... Continue reading "Verb Alternations: Body-Part, Causative, and Dative Shifts" »

The morpheme is the smallest, indivisible unit of semantic content or grammatical function from which words are made. Words can be classified into monomorphemic or simplex words ('faith' or 'week') and polymorphemic or complex words ('faithfully' or 'weekly'). 'Faith' and 'week' are free morphemes, while 'faithfully' and 'weekly' are bound morphemes that need to be attached to others. Bound morphemes can be prefixes, suffixes, or infixes.

Free morphemes act as bases to which other morphemes are attached to form derivatives. 'Mother' and 'faith' are examples of simplex bases, while 'faithfulness' is an example of a complex base composed of multiple morphemes.

'Teeth' and 'tables' are examples of nouns in the plural form, with 'tables' showing... Continue reading "Understanding Morphemes: Simplex and Complex Words" »

Simple Machines and Mechanical Advantage

Simple machines are devices that make work easier. They do this by changing the magnitude or direction of a force. Many simple machines are combined to create complex machines.

Wheel and Axle

A wheel is attached to a central axle so that when one turns, the other must turn. A longer motion at the wheel's edge is converted to a shorter, more powerful motion at the axle. Conversely, a short, powerful force at the axle moves the wheel's edge a greater distance.

Pulley System

A single pulley simply reverses the direction of a force. When two or more pulleys are connected together, they permit a heavy load to be lifted with less force. The trade-off is that the rope's end must move a greater distance than the... Continue reading "Simple Machines: A Comprehensive Guide to Mechanical Advantage" »