it's not magic, it's physics!

Hi and welcome to my post! I want talk you about a concept very importan in the physical and engineering: mass center and show one of the very interesting things that you can do with this concept:

the center of mass represents the point at which we assume that the mass of an object is concentrated for study. It is the center of symmetry of mass distribution of a particle system.

For simple rigid objects with uniform density, the center of mass is located in the centroid. Sometimes the center of mass is nowhere on the object. The center of mass of a ring, for example, is located at its center, where there is no material.

However, when the shape of the object is more complicated it is necessary to resort to a more general mathematical definition of the center of mass:

For a system in which the position of each particle is known, the position of the center of mass is the weighted sum of the position vectors, which points to the center of mass of each object in a system

Where:

• n Is the number of particles that compound the system.

• Vector position of the center of mass and of each of the particles that make up the system with respect to the same reference system. Its unit of measurement in the International System is the metro (m).

• Total mass of the body and each respective particle that makes up the system. Its unit of measurement in the International System is the kilogram (kg)

A quick technique that allows us to avoid using vector arithmetic is to find, separately, the center of mass of the components along each axis

Along the X-axis, the position of the mass center is

and on the Y-axis

Now that you have seen how to find the center of mass for an object or a group of objects, I would like to show you how to do the trick shown at the beginning of the post. for this, you only need a cutlery and a spoon that have approximately the same weight and a small stick mounts (in my case I did not have one so use the key to unlock my phone)!

Take the spoon and place it between the teeth of the fork so that it is just, as shown in the picture

Finally, place the toothpick in the center hole of the fork so that when placed on the surface you can hold the fork and the fork. The structure is kept in balance because its center of mass, which is at the end of the stick is in equilibrium

This is all for now. I hope you enjoyed my post as much as I enjoyed doing it :)

References:

1. https://www.fisicalab.com/apartado/centro-de-masas#contenidos
2. https://es.khanacademy.org/science/physics/linear-momentum/center-of-mass/a/what-is-center-of-mass