TOPIC: Avogadro's law (1811)

TOPIC: Avogadro's law (1811)

"If two kinds of gas (or more) of the same volume, then the gases just as much as the number of molecules, respectively, from the same temperature and pressure, and also

Archimedes ' law (+ 250 BCE)

Archimedes ' law (+ 250 BCE)

"If an object is dipped into the liquid, then something that thing will get the same amount of pressure with the infiltration of liquid weighing by the object".

Learn Physics-vibration and free vibration with damping

Learn Physics-vibration and free vibration with damping

Vibration analysis

Basic vibration analysis can be understood by studying the model simple mass-spring-damper. Complex structures such as the car body can be modelled as "sum" model of mass-spring-damper. This Model is an example of a simple harmonic oscillator

Vibration

Vibration analysis

Free vibration without silencer

In the simplest model of the attenuation is considered negligible, and there is no outside force affecting mass (free vibration).

In these circumstances the prevailing style in the spring the long stretch comparable to Fs x according to Hooke's law, or when it is formulated mathematically:

Fs =-k x

with the k is the spring constant.

According to Newton's second law force posed is proportional to the acceleration of the mass:

Σ F = ma = m {x} = m {d ^ 2 x}: {dt ^ 2} =

Since F = Fs, we get the following ordinary differential equation:

m {x} + k x = 0.

Simple harmonic motion-spring system

If we assume that we start the vibration system with spring-loaded so far A stretch and then release it, the above equations solution describing the mass movements are:

x (t) = A 2cos (2pi. fn. t)

This solution suggests that the mass will oscillate in simple harmonic motion having an amplitude of A frequency and fn fn number is one of the most important quantities in vibration analysis, and called the undamped natural frequency. For a simple mass-spring system, the fn is defined as:

fn = {1: {2pi}}. root {k: m}

Note: the angular frequency ω (ω = 2πf) and units of radians per second is often used in equations because it simplifies the equations, but the magnitude is usually converted into a "standard" frequency (units of Hz) when stating the frequency of the system.

When the mass and stiffness (a k) Note the frequency of vibration of the system will be determined using the formula above.

Vibration

Vibration analysis

Free vibration with damping

When the attenuation is taken into account, means style silencer also applies on a mass in addition to the force caused by stretching the spring. When moving in a fluid object will get attenuation due to the viscosity of the fluid. The style of this viscosity is proportional to the speed of objects. Due to constant viscosity (viscosity) c is a coefficient with units of reducer, N s/m (SI)

The solution to this equation depends on the magnitude of the damping. When damping is small enough, the system will still vibrate, but will eventually stop. This State is called less mute, and is most cases get attention in the analysis of the vibration. When the attenuation is enlarged so that it reaches the point when the system is no longer oscillates we reach a point of critical damping. When the attenuation is added through this critical point of the system referred to in the State through the mute.

To characterize the amount of attenuation in the system used a ratio called the damping ratio. This ratio is the ratio between the actual amount of attenuation attenuation is required to reach the point of critical damping.

Damped natural frequency less than the undamped natural frequency, however, for many practical cases the damping ratio is relatively small, and hence the difference is negligible. Therefore the damped and undamped description is often not mentioned when declaring natural frequency.

Physics waves and wave length

Physics waves and wave length

The waves are vibrations that propagate. The ideal form of a wave motion sinusoide will follow. In addition to electromagnetic radiation and gravitational radiation, which may be able to walk through a vacuum, there are waves on a medium (which because of changes the shape can generate elastic restoring forces) where they can run and can move the energy from one place to another without causing the particles of the medium move permanently; i.e. There is no displacement en masse. In fact, any special point oscillating around one particular position can have an effect on the penis.

A medium called:

linear if different waves at any particular point in the medium can be summed up,

limited if restricted, otherwise it is called unlimited

physical characteristics of uniform if not changed at different points

isotropic in its physical characteristics if the "same" in different directions

The Wavelength

The wavelength is the distance between repeating units of a wave pattern. Usually have denoted the letter lambda (λ) Greece.

In a sine wave, the wavelength is the distance between the peaks.

The x Axis represents length, and I represent the quantity varies (e.g. air pressure for a sound wave or electric or magnetic field strength for light), at a point in the function of time x.

Wavelength λ has an inverse relationship to frequency f, number of peaks to pass a point in a given time. Panjan wave is equal to the speed of the wave divided by the frequency of the wave. When dealing with electromagnetic radiation in a vacuum, this speed is the speed of light c, untuku signal (waves) in the air, it is the speed of sound in air. Connection is::

λ = {c}: {f}

λ = wavelength of a sound wave or electromagnetic waves

c = speed of light in a vacuum = 299, 792.458 km/d ~ 300.000 km/d = 300,000,000 m/s or

c = speed of sound in air = 343 m/s at 20 ° C (68 ° F)

f = the frequency of the wave

Electromagnetic waves

Electromagnetic waves

can be described as two waves of transversal propagated in two perpendicular plane of magnetic field and electric field. Towards magnetic waves will push the electric waves, and vice versa, while climbing, wave power will push the wave magnet. The Diagram above shows a light wave propagating from left to right with the electric field in the vertical plane and horizontal plane on the magnetic field.