📘 Complex Circuits
Most real-world electronics aren’t just series or parallel—they are Combination (Complex) Circuits. To solve these, we use “Circuit Reduction” to simplify t...
Most real-world electronics aren’t just series or parallel—they are Combination (Complex) Circuits. To solve these, we use “Circuit Reduction” to simplify t...
Ohm’s Law defines the relationship between the three most basic electrical quantities. It states that the current flowing through a conductor is directly pr...
In a parallel circuit, components are connected across the same two points, creating multiple paths (branches) for the current. This is how your home is wir...
Power in circuits describes how quickly electrical energy is transferred or transformed. Using Joule’s Law, we can determine how much energy is converted in...
In a series circuit, components are connected end-to-end, forming a single loop. There is only one path for the current to take. If that path is broken, the...
Materials are classified by how easily they allow electrons to move through them. Conductors let them flow freely, while insulators hold onto them tightly.
Electric charge is a fundamental property of matter. Particles with charge exert forces on each other: like charges repel, while opposite charges attract.
An Electric Field is a map of the force that a “test charge” would feel at any point in space. It allows us to describe the influence of a charge without ne...
The Electric Force is the interaction between two charged objects. Like gravity, it acts over a distance, but it is significantly stronger and can both attr...
Electric Potential is the amount of electric potential energy per unit charge. We often refer to the difference in potential between two points as Voltage.
When something moves in a circle, it’s always changing direction. Centripetal force is the force that pulls an object toward the center of the circle to kee...
Sometimes a force isn’t acting straight up, down, or sideways. Force components break a force into parts that point along easier directions (like horizontal...
A free-body diagram (FBD) is a simple drawing that shows all the forces acting on an object. It helps you see what’s pushing, pulling, or lifting the object...
Friction is a force that tries to stop objects from sliding or moving when they touch each other. It’s why things slow down when you push them and why you d...
An inclined plane is a flat surface tilted at an angle, allowing objects to move up or down more easily than lifting them straight vertically. Studying forc...
Newton’s First Law, often called the law of inertia, explains that objects keep doing what they are doing unless acted on by an external force. A stationary...
Newton’s Second Law explains how forces change the motion of objects. It tells us that the acceleration of an object depends directly on the net force appli...
Every force comes with a partner. Newton’s Third Law tells us that whenever one object exerts a force on another, the second object pushes back with an equa...
A spring exerts a force when it is stretched or compressed. This force, called the spring force, always acts to restore the spring to its natural length.
In physics, objects often interact. A system of objects lets us study multiple connected bodies, understanding how forces and motion affect each part and th...
Different forces act in different ways. Some forces pull objects downward, some push upward, and others resist motion or pull through ropes and cables.
True weight is the force of gravity pulling you downward. Apparent weight is the support force pushing up on you, like the force from a floor or scale. They...
Gravitational field strength tells us how strong gravity is at a particular location. It describes the force per unit mass experienced by an object due to g...
Kepler’s First Law, also called the Law of Ellipses, states that every planet moves in an elliptical orbit, with the Sun located at one focus of the ellipse...
Kepler's Second Law, the Law of Equal Areas, states that a line connecting a planet to the Sun sweeps out equal areas in equal intervals of time.
Kepler's Third Law, the Law of Harmonies, shows a precise mathematical link between a planet's orbital period and its average distance from the Sun.
For a satellite to maintain a stable circular orbit, the gravitational pull of the planet must provide exactly enough centripetal force to keep the satellit...
Newton's Law of Universal Gravitation states that every particle in the universe attracts every other particle with a force that is directly proportional to...
In science, understanding the difference between accuracy and precision is crucial for reliable data. This page will define what each term means and show you...
Dimensional analysis is a powerful tool in physics that goes beyond just converting units. It’s a fundamental way to understand and check equations by focus...
In physics, graphs are powerful tools. They help us see patterns, understand relationships, and make predictions about how different measurements are connec...
Physics uses a special language of symbols (like single letters) and short ways of writing (notation) to stand for things we measure and how they connect. L...
Physics needs measurements that everyone understands, no matter where they are. That’s where the SI system comes in. It’s the standard way we measure things...
When you add or subtract measurements, significant figures follow a different rule than multiplying or dividing. For adding and subtracting, it’s all about ...
When you multiply or divide measurements, the rules for significant figures are different from adding or subtracting. Here, we focus on the total number of ...
Significant figures are a way to show how precise a measurement is. Knowing which digits are “significant” helps us avoid pretending our measurements are mo...
Every measurement you make has some amount of uncertainty. This is a fundamental concept in science and engineering, as it reminds us that no tool is perfec...
In 1820, Hans Christian Ørsted noticed a compass needle move when it was near a wire carrying a current. This was the birth of Electromagnetism: the discove...
A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. Even though ...
A magnetic field doesn’t just sit there—it exerts a force. However, magnetism is “picky.” A magnetic field will only exert a force on a charge if that charg...
The relationship between electricity and magnetism is a two-way street. If you put electricity into a magnetic field, you get motion (a motor). If you put m...
A transformer is a device that changes the voltage of an alternating current (AC). It is the bridge between the high-voltage power lines traveling across th...
The Conservation of Momentum states that the total momentum of a system remains constant if no external net force acts on it. Momentum can be transferred be...
The Impulse–Momentum Theorem states that the impulse applied to an object is equal to its change in momentum. It is the fundamental bridge between forces ac...
Impulse describes the effect of a force acting over a period of time. It is directly responsible for changing an object’s momentum.
Momentum is a measure of how much motion an object has. It depends on both the object’s mass and its velocity, making it especially important when analyzing...
Acceleration is the rate at which an object’s velocity changes. If you are speeding up, slowing down, or changing direction, you are accelerating. It is the...
Distance is the total path traveled, a scalar quantity. Displacement is the change in position from start to end, a vector quantity.
Free fall is the motion of an object when gravity is the only force acting on it. In free fall, the object’s acceleration is constant and always directed do...
Kinematics is the study of how objects move, focusing on their position, velocity, and acceleration without considering the forces that cause the motion.
A position-time graph is a powerful tool that shows an object’s location over time, allowing you to quickly determine its velocity and direction of motion.
Speed tells you how fast something is going (a scalar quantity), while velocity tells you how fast and in what direction (a vector quantity).
A velocity-time graph shows an object’s velocity over time. The slope of the line represents its acceleration, and the area under the curve represents its d...
Projectile motion describes the curved, parabolic path an object takes when launched into the air. It’s analyzed by treating the motion as two independent c...
Relative velocity is the velocity of an object as perceived from a specific frame of reference. It is a fundamental concept in kinematics, often calculated ...
Uniform circular motion (UCM) describes an object moving in a circular path at a constant speed. Due to its continuously changing direction, the object’s ve...
Vector addition combines two or more vectors to find a single resultant vector, often using the graphical head-to-tail method. Vector subtraction is a speci...
A scalar quantity is a measurement that only has magnitude (a size or amount), while a vector quantity has both magnitude and a specific direction.
Angular motion describes the movement of an object as it rotates around a fixed axis. Just as we use distance and speed for straight-line movement, we use a...
Conservation of Angular Momentum states that if no external torque acts on a system, the total angular momentum of that system remains constant.
Rotational Inertia (also called the Moment of Inertia) is an object’s resistance to changes in its rotation. It is the rotational counterpart to mass in lin...
Torque is a measure of the force that can cause an object to rotate about an axis. Just as force causes an object to accelerate linearly, torque is what cau...
Beats occur when two sound waves with slightly different frequencies overlap, creating a repeating pattern of loud and soft sound.
The Doppler Effect is the change in the observed frequency of a wave when the source of the wave and the observer are moving relative to each other. It expl...
Periodic motion is any motion that repeats itself at regular time intervals. From the ticking of a clock to the orbit of a planet, periodic motion is the he...
Simple Harmonic Motion (SHM) is a specific type of periodic motion. It occurs when an object is moved away from an equilibrium position and experiences a re...
Sound is a longitudinal mechanical wave produced by vibrating objects. It travels through a medium by creating a series of high-pressure “squeezes” and low-...
A standing wave occurs when a wave is reflected back and forth between two boundaries. The incoming wave and the reflected wave interfere so perfectly that ...
Unlike solid objects, two waves can exist in the exact same place at the exact same time. When they overlap, they don’t bounce off each other—they combine. ...
A wave is a disturbance that travels through a medium, transporting energy from one location to another without transporting matter. To understand waves, we...
The Law of Conservation of Energy states that the total energy of an isolated system remains constant. Energy can change form, but the total amount never ch...
Energy is defined as the capacity to do work. It is a scalar quantity that comes in many forms—such as motion, position, heat, and light—but it can never be...
Power is the rate at which work is performed or energy is transferred. In physics, it doesn’t just matter how much work you do; it matters how fast you do i...
The Work-Energy Theorem states that the net work done by all forces acting on an object is equal to the change in its kinetic energy.
In physics, work is done when a force acts upon an object to cause a displacement. It is the measure of energy transfer that occurs when an object is moved ...