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

1. Key Terms in Kinematics

• Motion: Change in position of an object over time.
• Position (x): The location of an object in space, often relative to a reference point.
• Displacement (Δx): Change in position, taking into account direction.
• Speed (v): The rate of change of distance with respect to time (scalar quantity).
• Velocity (v): The rate of change of displacement with respect to time (vector quantity).
• Acceleration (a): The rate of change of velocity with respect to time.
• Deceleration: Negative acceleration (slowing down).

2. Fundamental Physics Equations

• Average Speed (v_avg): v_avg = Δx / Δt (where Δt is the time interval).
• Average Velocity (v_avg): v_avg = Δx / Δt (with direction).
• Instantaneous Velocity (v): v = dx/dt (the derivative of displacement

Electrical Charge and Magnetic Field

Electrical charge is a property of matter related to the proportion of protons and electrons in its atoms. Positive electrical charge: this is produced when atoms lose some of their electrons. Negative electrical charge: this is produced when atoms gain some of their electrons. A magnet forms around itself a magnetic field, which is the area in space where its force can be felt.

Energy: Definitions and Internal Energy

Energy is the capacity bodies have to produce changes in themselves and other bodies. Electrical energy is produced by the movement of charges in and through a conductor. Electromagnetic energy is transported by electrical and magnetic waves. Chemical energy is produced during chemical processes.... Continue reading "Energy Types, Heat Transfer and Electrical Charge" »

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" »