Conical pendulum
3 forces acting on a conical pendulum Gravity(=mg): The force the Earth pulls. Tension: The force applied to both ends of the thread. Tension is always directed to the center from both ends. Centripetal force(Fc): The … more
Force to move the pendulum
Tension by gravity In physics, tension is the force on a string connecting two objects. Generally, the tension is calculated from both ends toward the center. When the length of the pendulum is \(l\), let’s consider … more
Moment of Inertia (3D)
● It’s a tube. The radius of the tube is outside: inside = 0.75: 1. There is no rolling friction. ● It’s a tube. The radius of the tube is outside: inside = 0.5: 1. There … more
Connection of springs
You can hang multiple springs by touching (or clicking) the screen. What’s the difference when connecting multiple springs in series or parallel? (Notice) All springs and weights each have the same properties (mass, spring constant). The … more
Transistor application circuit
The above simulation is based on a circuit that actually works. The transistor uses C1815(general-purpose NPN switching transistor). The resistance connected to the base is 100kΩ, and the resistance connected to the emitter is 100Ω. Transistor … more
Structure of an ammeter
Ammeter The strength of the current in the electrical circuit is measured using an ammeter. There is a rotor with a coil wound inside the ammeter. When the current flows through the ammeter, the coil and … more
Gulliver’s Nutrition
Why did the King of Lilliput serve 1728 meals to Gulliver? This is because the volume of two objects that resemble each other in three dimensions is proportional to the cube of length. Since Gulliver’s height … more
Serial Parallel Circuit 3
Resistance Electrical resistance is a property of a material that impedes the flow of electric current. The unit of resistance is the ohm(Ω). When a voltage of 1V is applied, the conductor’s resistance that allows a … more
Dissolution Process
Dissolving Dissolving means that the solute diffuses into the solvent and mixes. It is a common case that salt or sugar is dissolved in water. Solvents are often liquid, mostly water. The Earth’s atmosphere is a … more
Rectifier Circuit
Diode Diodes are electronic components that pass current in only one direction. The direction in which current can flow through the diode is called ‘forward,’ and the direction in which current cannot flow through the diode … more
The principle of LED
LED LEDs are electronic devices that emit photons. LEDs have higher efficiency and longer life than bulbs. Basically, LEDs have a structure like a p-n junction diode. The p-n junction diode is made by attaching a … more