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

Mechanisms of the Vestibular System

Vestibular System Sensitivity to Acceleration: Mechanism

The vestibular system is sensitive to acceleration (linear or rotational) through the following mechanism:

• Semicircular Canals: There are three semi-circular canals, rotated 90 degrees relative to each other.
• Each canal is sensitive to acceleration in a different plane.
• The canals are filled with fluid (endolymph), which lags behind head movement, stimulating sensory hair cells.

Detecting Head Orientation (Tilt) via the Vestibular System

If the vestibular system is sensitive to acceleration, it can also detect the orientation (tilt) of the head because of its sensitivity to gravity. The otolith organs (utricle and saccule) contain dense structures (otoconia)... Continue reading "Mechanisms of Sensory Perception: Vestibular and Auditory Systems" »

WEEK4

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" »

Middle English Pronouns, Verbs, and Lexical Change

2nd Person Forms and Address

2nd p. sg and pl in the Middle English period: Very different depending on whom you were addressing. The upper class used “ye” (plural of politeness), and lower-class speakers also used “ye” to address the upper class. The lower class among themselves used “thou” (singular). The upper class also used it to address the lower class. Objects: “thee” (sg), “you” (pl).

Pronouns and Relative Forms

• Relative pronouns and demonstratives: OE pe / demonstrative + pe.
• 12th century: that appears as a relative/interrogative marker.
• Introduction of wh-relatives and interrogative forms — frequency increases into Modern English.
• One replaces the OE indefinite pronoun

Fundamental Concepts of Energy and Work

• 1. Which of these is measured in joules? Energy
• 2. The two main types of energy discussed: Kinetic & Potential
• 3. The work-energy theorem: The net work done on an object equals the change in its kinetic energy.
• 4. Kinetic energy: The energy of movement.
• 5. The Law of Conservation of Energy: Energy can neither be created nor destroyed.
• 6. Potential energy: The energy of position.
• 7. Pendulum potential energy: Highest when at the top of its swing.
• 8. Inelastic collision: A collision where some energy is converted into other forms.
• 9. Chemical energy: Energy stored in chemical bonds.

Machines, Power, and Efficiency

• 6. Which machine has 100% efficiency? No real machine has 100% efficiency.
• 7. Rube Goldberg: Famous