law of universal gravitation

uniform circular motion

plasma state new research

inside spere potential difference equation

inside spere potential difference

kepelar law

For a more historical approach, see in particular the articles Astronomia nova and Epitome Astronomiae Copernicanae.

In astronomy, Kepler's laws of planetary motion are three scientific laws describing the motion of planets around theSun.

Figure 1: Illustration of Kepler's three laws with two planetary orbits.
(1) The orbits are ellipses, with focal points ƒ₁ and ƒ₂for the first planet and ƒ₁ and ƒ₃ for the second planet. The Sun is placed in focal point ƒ₁.

(2) The two shaded sectors A₁ and A₂ have the same surface area and the time for planet 1 to cover segment A₁ is equal to the time to cover segment A₂.

(3) The total orbit times for planet 1 and planet 2 have a ratio a₁^3/2 : a₂^3/2.

Astrodynamics
Orbital mechanics
Equations[hide] Kepler's laws Tsiolkovsky rocket equation Vis-viva equation
Efficiency measures[show]
v t e

1. The orbit of a planet is an ellipse with the Sun at one of the twofoci.
2. A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.^[1]
3. The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.

Most planetary orbits are almost circles, so it is not apparent that they are actually ellipses. Calculations of the orbit of the planet Mars first indicated to Kepler its elliptical shape, and he inferred that other heavenly bodies, including those farther away from the Sun, have elliptical orbits also.

Kepler's work improved the heliocentric theory of Nicolaus Copernicus, explaining how the planets' speeds varied, and using elliptical orbits rather than circular orbits with epicycles.^[2]

Isaac Newton showed in 1687 that relationships like Kepler's would apply in the solar system to a good approximation, as consequences of his own laws of motion and law of universal gravitation.

So Kepler's laws are part of the foundation of modern astronomy andphysics.^[3]

Angular velocity

In physics, the angular velocity is
defined as the rate of change of
angular displacement and is a vector
quantity (more precisely, a
pseudovector ) which specifies the
angular speed ( rotational speed ) of an
object and the axis about which the
object is rotating. The SI unit of
angular velocity is radians per second,
although it may be measured in other
units such as degrees per second,
degrees per hour, etc. Angular
velocity is usually represented by the
symbol omega (ω, rarely Ω).
The direction of the angular velocity
vector is perpendicular to the plane of
rotation, in a direction which is
usually specified by the right-hand
rule . [1]

momentum

In classical mechanics, linear momentum or translational momentum (pl. momenta; SI unit kg m/s, or equivalently, N s) is the product of the mass and velocity of an object. For example, a heavy truck moving quickly has a large momentum—it takes a large or prolonged force to get the truck up to this speed, and it takes a large or prolonged force to bring it to a stop afterwards. If the truck were lighter, or moving more slowly, then it would have less momentum.
Like velocity, linear momentum is a vector quantity, possessing a direction as well as a magnitude

Linear momentum is also a conserved quantity, meaning that if a closed system is not affected by external forces, its total linear momentum cannot change. In classical mechanics, conservation of linear momentum is implied by Newton's laws; but it also holds in special relativity (with a modified formula) and, with appropriate definitions, a (generalized) linear momentum conservation law   holds in electrodynamics quantum mechanics, quantum field theory, and general relativity electrodynamics

types of collison

1. A perfectly elastic collision is defined as one in which there is no loss of kinetic energy in the collision. In reality, any macroscopic collision between objects will convert some kinetic energy to internal energy and other forms of energy, so no large scale impacts are perfectly elastic. However, some problems are sufficiently close to perfectly elastic that they can be approximated as such. In this case, the coefficient of restitution equals to one.
2. An inelastic collision is one in which part of the kinetic energy is changed to some other form of energy in the collision. Momentum is conserved in inelastic collisions (as it is for elastic collisions), but one cannot track the kinetic energy through the collision since some of it is converted to other forms of energy. In this case, coefficient of restitution does not equal to one.

collision

A collision is an isolated event in which two or more moving bodies (colliding bodies) exert forces on each other for a relatively short time.
Although the most common colloquial use of the word "collision" refers to accidents in which two or more objects collide, the scientific use of the word "collision" implies nothing about the magnitude of the forces.
Some examples of physical interactions that scientists would consider collisions:

• An insect touches its antenna to the leaf of a plant. The antenna is said to collide with leaf.
• A cat walks delicately through the grass. Each contact that its paws make with the ground is a collision. Each brush of its fur against a blade of grass is a collision.

Some colloquial uses of the word collision are:

• automobile collision, two cars colliding with each other
• mid-air collision, two planes colliding with each other
• ship collision, two ships colliding with each other

anatomy of an n degree polynomial function

physics function

mineral physics

Mechanical energy

From Wikipedia, the free encyclopedia

An example of a mechanical system: A satellite is orbiting the Earth only influenced by the conservative gravitational force and the mechanical energy is therefore conserved. The satellite is accelerated towards the Earth with an acceleration perpendicular to the velocity. This acceleration is represented by a green acceleration vector and the velocity is represented by a red velocity vector. Though the velocity is constantly changed with the direction of the vector because of the acceleration vector, the speed of the satellite is not since the magnitude of the velocity vector remains unchanged.

In the physical sciences, mechanical energy is the sum of potential energy and kinetic energy. It is the energy associated with the motion and position of an object. The principle of conservation of mechanical energy states that in an isolated system that is only subject to conservative forces the mechanical energy is constant. If an object is moved in the opposite direction of a conservative net force, the potential energy will increase and if the speed (not the velocity) of the object is changed, the kinetic energy of the object is changed as well. In all real systems, however, non-conservative forces, like frictional forces, will be present, but often they are of negligible values and the mechanical energy's being constant can therefore be a useful approximation. In elastic collisions, the mechanical energy is conserved but in inelastic collisions, some mechanical energy is converted into heat. The equivalence between lost mechanical energy (dissipation) and an increase in temperature was discovered by James Prescott Joule.
Many modern devices, such as the electric motor or the steam engine, are used today to convert mechanical energy into other forms of energy, e.g. electrical energy, or to convert other forms of energy, like heat, into mechanical energy

energy unit

Main article: Units of energy

This section requires expansion. (January 2013)

Energy, like mass, is a scalar physical quantity. The joule is the International System of Units (SI) unit of measurement for energy. It is a derived unit of energy, work, or amount of heat. It is equal to the energy expended (or work done) in applying a force of one newton through a distance of one metre. However energy is also expressed in many other units such as ergs, calories, British Thermal Units, kilowatt-hours and kilocalories for instance. There is always a conversion factor for these to the SI unit; for instance; one kWh is equivalent to 3.6 million joules.^[6]
The SI unit of power (energy per unit time) is the watt, which is simply a joule per second. Thus, a joule is a watt-second, so 3600 joules equal a watt-hour. The CGS energy unit is the erg, and the imperial and US customary unit is the foot pound. Other energy units such as the electron volt, food calorie or thermodynamic kcal (based on the temperature change of water in a heating process), and BTU are used in specific areas of science and commerce and have unit conversion factors relating them to the joule.
Because energy is defined as the ability to do work on objects, there is no absolute measure of energy. Only the transition of a system from one state into another can be defined and thus energy is measured in relative terms. The choice of a baseline or zero point is often arbitrary and can be made in whatever way is most convenient for a problem. For example in the case of measuring the energy deposited by X-rays as shown in the accompanying diagram, conventionally the technique most often employed is calorimetry. This is a thermodynamic technique that relies on the measurement of temperature using a thermometer or of intensity of radiation using a bolometer.
Energy density is a term used for the amount of useful energy stored in a given system or region of space per unit volume. For fuels, the energy per unit volume is sometimes a useful parameter. In a few applications, comparing, for example, the effectiveness of hydrogen fuel to gasoline it turns out that hydrogen has a higher specific energy than does gasoline, but, even in liquid form, a much lower energy density.

common formula p , i , v ,r

kinetic energy

motion

Force

From Wikipedia, the free encyclopedia

For other uses, see Force (disambiguation) and Forcing (disambiguation).

Force
Forces are also described as a push or pull on an object. They can be due to phenomena such as gravity, magnetism, or anything that might cause a mass to accelerate.
Common symbols	F, F
SI unit	newton
In SI base units	1 kg·m/s2
Derivations from other quantities	F = m a

In physics, a force is any interaction which tends to change the motion of an object.^[1] In other words, a force can cause an object with mass to change itsvelocity (which includes to begin moving from a state of rest), i.e., to accelerate. Force can also be described by intuitive concepts such as a push or a pull. A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newtons and represented by the symbol F.

The original form of Newton's second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time. If the mass of the object is constant, this law implies that the acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, and is inversely proportional to the mass of the object. As a formula, this is expressed as:

where the arrows imply a vector quantity possessing both magnitude and direction.

Related concepts to force include: thrust, which increases the velocity of an object; drag, which decreases the velocity of an object; and torque which produces changes in rotational speed of an object. In an extended body, each part usually applies forces on the adjacent parts; the distribution of such forces through the body is the so-called mechanical stress. Pressure is a simple type of stress. Stress usually causes deformation of solid materials, or flow in fluids.

physics greater scientist Galileo Galilei

Galileo Galilei

From Wikipedia, the free encyclopedia

"Galileo" redirects here. For other uses of "Galileo", see Galileo (disambiguation). For other uses of "Galileo Galilei", see Galileo Galilei (disambiguation).

Galileo Galilei
Portrait of Galileo Galilei by Giusto Sustermans
Born	15 February 1564 Pisa, Duchy of Florence, Italy
Died	8 January 1642 (aged 77) Arcetri, Grand Duchy of Tuscany, Italy
Residence	Grand Duchy of Tuscany, Italy
Nationality	Italian
Fields	Astronomy, physics, natural philosophy and mathematics
Institutions	University of Pisa University of Padua
Patrons	Cardinal del Monte Fra Paolo Sarpi Prince Federico Cesi Cosimo II de Medici Ferdinando II de Medici Maffeo Barberini
Alma mater	University of Pisa
Academic advisors	Ostilio Ricci[1]
Notable students	Benedetto Castelli Mario Guiducci Vincenzo Viviani[2]
Known for	Kinematics Dynamics Telescopic observational astronomy Heliocentrism
Signature
Notes His father was the musician Vincenzo Galilei. Galileo Galilei's mistress Marina Gamba (1570 – 21 August 1612?) bore him two daughters (Maria Celeste (Virginia, 1600–1634) and Livia (1601–1659), both of whom became nuns) and a son Vincenzo (1606–1649), a lutenist.

Galileo Galilei (Italian pronunciation: [ɡaliˈlɛːo ɡaliˈlɛi]; 15 February 1564^[3] – 8 January 1642), often known mononymously as Galileo, was an Italian physicist, mathematician, engineer, astronomer, and philosopher who played a major role in the scientific revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism. Galileo has been called the "father of modern observational astronomy",^[4] the "father of modern physics",^[5][6] the "father of science",^[6][7] and "the Father of Modern Science".^[8]
His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the discovery of the four largest satellites of Jupiter (named the Galilean moons in his honour), and the observation and analysis of sunspots. Galileo also worked in applied science and technology, inventing an improved military compass and other instruments.
Galileo's championing of heliocentrism was controversial within his lifetime, a time when most subscribed to either geocentrism or the Tychonic system.^[9] He met with opposition from astronomers, who doubted heliocentrism due to the absence of an observed stellar parallax.^[9] The matter was investigated by the Roman Inquisition in 1615, which concluded that heliocentrism was false and contrary to scripture, placing works advocating the Copernican system on the index of banned books and forbidding Galileo from advocating heliocentrism.^[9][10] Galileo later defended his views in Dialogue Concerning the Two Chief World Systems, which appeared to attack Pope Urban VIII, thus alienating not only the Pope but also the Jesuits, both of whom had supported Galileo up until this point.^[9] He was tried by the Holy Office, then found "vehemently suspect of heresy", was forced to recant, and spent the rest of his life under house arrest.^[11][12] It was while Galileo was under house arrest that he wrote one of his finest works, Two New Sciences, in which he summarised the work he had done some forty years earlier, on the two sciences now called kinematics and strength of materials.^[13][14]

semi conductor

radio wave

type of state

plasma