Notes, summaries, assignments, exams, and exercises for Physics for Secondary education

Key Figures in Astronomical and Physical Science

Aristotle

• Proved that the Earth is spherical.
• Believed that the Earth was at the center of the universe.

Aristarchus

• He was the first to state that the Sun, and not the Earth, was the center of our universe.
• Used simple geometry to estimate the size of the Sun and Moon and their relative distances.

Ptolemy

• Made a model called the Ptolemaic system, concluding all astronomical objects move at constant speeds in circular orbits.
• Ptolemy built his model to fit this idea. The Ptolemaic model is one of the longest upheld scientific theories in history; it was the cornerstone of astronomy for 1,500 years.

Copernicus

• Concluded that the Sun was the center of the universe instead of the Earth.
• Promoted the concept

Light and Sound Waves

Light, when reflected from objects and reaching our eyes, allows us to see. Sound makes the eardrum—a membrane in the ear—vibrate. These vibrations are transmitted to the brain by nerves.

How Light Is Produced

The Sun is the main source of light on Earth. We have also learned how to produce light:

• Using chemical energy: Burning fuel produces light (e.g., wood, oil, and gas).
• Using electrical energy: This is the case with lamps, televisions, or computer screens.

How Sound Is Produced

• Intensity: Sounds can be strong or weak. Intensity is the magnitude that varies when we regulate the volume; it is measured in decibels.
• Tone: Sound can be high or low. Tone is the characteristic that differentiates two musical notes with the same

Physics Fundamentals: Multiple Choice Questions

1. The SI base unit for mass is:
e. kilogram

2. For which of the following situations is the conservation of mechanical energy most likely to be a valid assumption?
b. a parachutist falls from a plane

3. The slope of a line drawn tangent to a point on the curve of a position versus time graph describes what concept?
c. instantaneous velocity

4. As an object falls towards Earth:
d. the upward acceleration of Earth is negligible because of its large mass

5. Mass differs from weight in that:
b. weight is a force and mass is not

6. The main difference between kinetic energy and potential energy is that:
b. Kinetic energy involves motion, and potential energy involves position

7. A lead ball and a book are

Essential Wave Phenomena Definitions

Wave Terminology

• Node: A point of zero amplitude on a standing wave.
• Resonance: The increase in the amplitude of a vibration that occurs when external vibrations match an object's natural frequency.
• Antinode: A point of maximum amplitude on a standing wave.
• Standing Wave: A wave that appears to stand in one place, even though it is really two waves interfering as they pass through each other.
• Reflection: The bouncing back of an object or a wave when it hits a surface through which it cannot pass.
• Hertz (Hz): Unit of measurement for frequency.
• Frequency: The number of complete waves that pass a given point in a certain amount of time.
• Wavelength: The distance between two corresponding parts of a wave.
• Amplitude: The

Electric Current (I)

In this formula, I represents the current (measured in amperes, A) and Q is the quantity of charge (measured in coulombs, C) flowing past a specific point in the circuit within a time interval t (measured in seconds).

One coulomb of charge is equivalent to the charge carried by 6.24 × 10¹⁸ electrons. Conversely, the charge carried by a single electron is equal to -1.602 × 10^-19 C.

Voltage (V)

Where V is the voltage drop (measured in volts, V) across a device, E is the amount of energy (measured in joules, J) transformed, and Q is the amount of charge (measured in coulombs, C) that passed through the device.

Energy (E)

Electric circuits are designed to transform electrical energy into other functional forms. The amount of energy

Work and Power in Physics

Work acts on a body when a force moves it through a distance; we say that force has done a job. Therefore, the work will be calculated as: W = F · s. The work unit in the SI is the Joule (J), which is defined as the work performed by applying a force of 1 Newton over 1 meter (1J = 1N · 1m).

Conditions for No Work

No work is done when:

• 1. There is no displacement (space is 0); the work is zero.
• 2. The force and displacement are perpendicular (90°).

Power and Efficiency

Power: The quantity that relates work over time; therefore, P = W / t. The SI unit is the Watt (W), defined as work performed at 1 Joule per second (1W = 1J / 1s). It can also be expressed as: P = F · v.

Efficiency: The performance of a machine is never 100%...

Force

A cause that can produce changes in the motion or shape of an object.

Action-at-a-Distance Forces

Forces whose effects are observed without the bodies needing to be in physical contact with each other.

Hooke's Law

The deformation of an elastic body is directly proportional to the force that produces it.

Scalar Quantities

Quantities defined by a number and a unit.

Vector Quantities

Magnitudes defined by a magnitude, direction, sense, and point of application. They are represented by a vector, which is an oriented segment in space.

Net Force

The single, resultant force equivalent to all forces acting on a particular body.

Equilibrium Conditions

A body is in equilibrium if the resultant of the forces acting on it is zero.

Static Equilibrium

A situation...

The Fundamentals of Motion

Motion is defined as a change in position of a body relative to a reference point. Motion can be determined in two ways:

• By analyzing the trajectory and the relationship between position and time.
• By using the position vector as a function of time.

Concepts for the Study of Kinematics

• Mobile Object: The object in motion.
• Trajectory: The path followed by the mobile object.
• Origin/Reference Point: The point used as a reference to determine the mobile object's position.
• Position: The location of the mobile object relative to the origin.
• Displacement (Δs = s_f - s_i): The change in position of a mobile object between two instants of movement. It is the final position minus the initial position.
• Distance Traveled (e): The total length

DC Generators: Contains a rectangular loop rotating in a uniform magnetic field. It consists of 2 main parts: the inductor, which creates the magnetic field, and the conductor, which is crossed by the lines of field strength. Operation: When the loop rotates, the flow of the magnetic field changes with time, and there is an emf. The ends of the loop connect to 2 rings that rotate with the coils. The connections to the external circuit are made via brushes. Starters: The three-phase stator winding of an asynchronous motor can be connected in star or triangle, depending on the network and voltage indicated on the motor's nameplate. There are 6 terminals for the 3 motor windings, but the connection terminal must be grounded. For the star connection,...

A physical deformity, affecting its strength or motion or any reason is subject to change pausagune situations. Vector magnitude of forces and Newton (N) are measured in international system. Point of application, indicating the strength of what reagiten points, and the force vector that represents the starting point. Is the numerical value of the power module. Coincides with the vector length. Meaning what direction the force is applied. A two-way direction of forces in the same direction may be, contrary to each other. Vector is indicated by the arrow on the end. Exploring the dynamic forces of physics responsible for the mechanical part is formed with the kinematics. Of contact forces, contact with body, must be shown to, diztantzia forces,...