## Elastic energy

Elastic (potential) energy stored in the spring The elastic energy is stored in the deformed spring. Also called ‘potential energy,’ and denoted by Ep. $Elastic \;energy \;E_p(J) = \frac{1}{2}kx^2$ m: Mass (kg) k: Spring constant (N/m) x: Deformation … 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 spring is very light, … 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 is about 12 times … more

## The principle of riding a swing

Kids have the know-how, but they can’t tell the principal. “How can you go so high?” Some principles are difficult to describe in words in the world, even if everyone knows. I think one of them is how to ride … more

## Period of Physical Pendulum

A pendulum that vibrates is one of a ‘simple pendulum’ or ‘physical pendulum.’ A simple pendulum is a case in which an object’s angular motion can be ignored, such as a small object suspended from a string. Most pendulums are … more