The center of gravity and mass (Ağırlık merkezi ve kütle)

The center of gravity and mass (Ağırlık merkezi ve kütle)
The center of gravity of an object is that point from which it can be suspended in any orientation without tending to rotate.

The center of gravity of an object and the center of mass are the same.

Mass and weight

Mass: (Kütle) (m) Mass is the quantity of matter it is a scalar quantity measured by equal-arm balance

It is formed of the total number of molecules or atoms of the body.
The mass of an object is constant. It has the same value everywhere.
On the earth, on the moon, at any other planets.
The unit of mass is kg in SI system.
1kg = 1000gr

The mass of any object is given as
M = d*V (density*volume)

Weight (Ağırlık): (W)
There is force acting on this object because of gravity and it is toward the center of the earth. It is called weight.
It is given as,
/W=m*g/

g is the gravitational acceleration.
g = 9.8m/s2 in SI system

The unit of weight and the unit of force are same. [W] = [F] = Newton in SI system

(Weight it the force exerted on the earth by the object)
The magnitude of gravity changes slightly from one planet to other. On the surface of the earth it gets smaller then at points having high altitudes.
In regions of space far from the earth where gravity is zero objects mould have no weight.

Torque

Torque (the moment of the force)
The ability of the force to rotate the body about some axis is measured by a quantity called the torque.

The torque because of a force F1 is given by this equation
Torque = ζ = F*d
Where d – is the distance between the point of rotation and the force perpendicular to the lever – moment arm. If the force is not perpendicular to the lever arm, there is an angle between the force and the level arm, in this case the torque provided by wrench is,
ζ = F*sinΘ*d

There is the torque because of Fy (vertical)
There is no torque because of Fx (horizontal)

Torque is a vector quantity/ the direction of the torque vector is along the axis of rotation and not in the direction of applied force.

The unit of torque is N*m (Newton. Metr) in SI system
The unit of torque is dyne*cm in SI system

The Mind and Physics

The mind has played a role in physics since the earliest days of quantum physics. The Fifth Solvay Conference in 1927 featured a debate between Niels Bohr and Albert Einstein about whether the mind and consciousness are (Bohr) or are not (Einstein) part of physics. Einstein's position has dominated mainstream physics for decades, but the battle simmered on for the entire twentieth century.



New Physics

Much of 20th-century physics has proceeded along the reductionist path that seeks quantum gravity at the intersection of the extended lines of quantum physics and relativity.

This reductionist path must always try to force into a stretched standard model the many phenomena of new physics that have been theorized or observed over recent decades:

* extra dimensions of space
* black holes
* dark matter and dark energy
* entanglement
* tunneling
* Bose-Einstein condensates
* neutrino mass
* radical theses about time and matter

the first lesson - The force

One of the most important units in physics is FORCE.
So let’s understand what is it?




Force is that which changes a body’s state or uniform motion in a straight line.
Ex: When you push or pull on object in a certain direction you exert a force on that object.

For instance gravity is a force which exerts on every object on the earth. In order to lift the object from the ground you need to exert an upward force that is greater than the weight of the object.

Any force is specified by its magnitude, direction and point of applying.

Force is a vector quantity. The addition and substraction of forces are the same as the addition and substraction of vectors.

The unit of force in SI system is Newton.
The unit of force in Gauss system is Dyne
1 N (Newton) = 100000 dynes

My physics

This year I joined to different physics olimpiads in my coentry - Kyrgyzstan. Here I am going to publish some units which may be useful for everybody who want to develope his/her knowledge of physics science and may be join to some international olimpiads of this science. I hope this blog will useful to somebody.