Rabu, 26 Desember 2012

Answer the Final test of English for special purpose

 By  Hafiful Hadi S
NIM RSA1C311018
Physics Education Student 2011

1.design a simple research about the kinetic energy associated with your daily life and arrange your report in accord with the sixth science process skills you have already understood.
In my diary life
When playing the ball on the ground I was exhausted what if more kicking the ball your body will be more tired. as well as the ball kicked, when we kick the ball hard will be thrown farther. apparently felt fatigue caused by a change in the energy of the motion of the body into kinetic energy to the ball. This energy causes the ball was thrown or moved from one position to another position.
   In physics, the energy possessed by a moving ball is called kinetic energy. Energy is the ability to do work. therefore when it is connected with the work in getting an equation:
Ek = 1/2 mv2
Ek = kinetic energy (J)
m = mass (kg)
v = velocity (m / s)

 of the equation is known that the kinetic energy depend on mass and velocity
as the ball of mass m is thrown with a certain velocity, it has a kinetic energy, the greater the mass and velocity, the greater the kinetic energy in the possessed
A ball with a mass of 1 kg thrown with a speed of 2 m / s then the above equation the kinetic energy obtained  was 2 j.

My predicting
What happens if a ball of mass m with an initial velocity in throwing on a rough floor, after a distance s beam is stopped. this means that the force experienced by the ball the opposite direction to
speed so that the ball is initially slowed and stopped. What about kinetic energy?

  Wtot = ΔEk = ½ mv2 (final) - ½ mv2 (initial) where v final = 0
so,
Wtot = - ½ mv2
kinetic energy turns negative value indicates a reduction / deceleration kinetic energy.c

Conclusion
Energy is the ability to do work. Kinetic energy is the energy possessed by a moving object, the amount depends on the mass and velocity of the object.


2.describe an experiment which associated with the following terms : pendulum, frictional force and highest point. then enter the terms into the procedure so that these terms included in your experiment.
simple pendulum experiment
calculate the period and frequency
Theory 
Pendulum is load with a rope tied to a place where the rope in use is not stretched.
period is the time that is needed to make one round
   T = t / n
T = period
t = time
n = many rounds

frequency is the time that it takes to make one round
  f = n / t
f = frequency (hz)
n = many rounds
t = time (s)
relationship between period and frequency
T = 1 / f or f = 1 / T 



Tools and materials is needed
1. stative
2. weight
3. thread
4. rule
5. stopwatch
6. paper
7. protractor
 

The procedures

1. prepare the tools mentioned above
2. pieces of thread that will be used throughout the 15 cm
3. tie one end of the pendulum on a string and the other end tied to the stative
4. give small deviation (no more than 10 degrees) to the pendulum
5. swing the pendulum to swing 20 times
6. count and record the time required by the stopwatch
7. look at how many seconds the pendulum reaches its highest point
8. count period by the equation T = t / n by ignoring friction forces that occurs
9. count the frequency of the equation f = 1 / T



3. make a simple calculation about electrical using the formula your well known. write done your solution and explain it by using your sentence ( change the number or symbol)

calculate electric current in the circuit series

Ohm's Law
The flow of electric current in a circuit does not end in the electric appliance. but circle back to the current source. Basically electric appliance electric current is inhibited. The relationship between electric current, voltage, and resistance can be likened to water flowing in a channel. The relationship is better known as Ohm's law.


 I = V / R or V = I. R
I = Current electricity (A)
V = voltage (volts)
R = Resistance (ohms)

from the equation above we know that the current strength is proportional to the voltage and inversely proportional to the resistance
or
voltage proportional to the current strength multiply resistance

Any current flowing through a conductor always have obstacles. If the electrical resistance is denoted by R. potential difference V, and a strong current I, the relationship between R, V, and I can mathematically be written:

Kirchoff law
The electrical current through a conductor can we view as the flow of river water. If the river is not branched, the amount of water at any place on the same river. So it is with an electric current.
The number of strong current into a branching point equal to the number of strong currents coming out of the branching point. The statement is often known as Kirchhoff's law because I was first presented by Kirchhoff.

So the equation is obtained:
I1 + I2 = I3 + I4 + I5
I get in = I out

or
  The electrical current that goes in a circuit similar to the amount of current out


Series circuit

According to Ohm's law: V = IR, the barriers are voltage V1 = IR1 R1 and R2 are the resistance voltage V2 = IR 2. Since the electric current flowing through the resistance R1 and R2 resistance, total voltage is VAC = IR1 + IR2.
Series circuit
According to Ohm's law: V = IR, the barriers are voltage V1 = IR1 R1 and R2 are the resistance voltage V2 = IR 2. Since the electric current flowing through the resistance R1 and R2 resistance, total voltage is VAC = IR1 + IR2.
Given the total voltage VAC is a strong electric current flowing in the circuit as above (not branched chain) at every point the same then VAC = IR1 + IR2 I R1 = I (R1 + R2) R1 = R1 + R2; R1 = total resistance The circuit as above is called a series circuit. Furthermore, written R1 Rs (R series) so that Rs = R1 + R2 + ... + Rn, where n = the number of resistors. So, if some pieces are assembled in series resistance, resistance value increases. As a result, a strong current flowing vanishingly small. This is what causes lights to be less bright (slightly dimmed) if arranged in series. The more lights that are strung together in series, flame increasingly dim. If the lights go out (break), the other lights off. 


sample questions
a series circuit consisting of R1 = 2 ohm R2 =  4 ohm, 8 ohm and R3 = R4 = 1 ohm with 2 volt voltage. specify
a. total circuit
b. Strong electrical currents
completion
a. to determine the total circuit of series circuit used formula
Rtot = R1 + R2 + R3 + R4
Rtot = 2 ohm + 4 ohm 0hm + 8 + 1 0hm
Rtot = 15 ohms
b. define strong electric current
I = V / R
I = 2 volts / 15 ohms
I = 0, 13 ampere


we get that if voltage 2 volts and total resistance is  15 ohm. so that current electricty it is 0,13 ampere


 4.make an essay about sound as a wave . then show at least three evidences and exemplifying about it.

Sound associated with the sense of hearing. imagine if the sound does not exist or is not able to hear the sense that the world would be so silent.
   The sound is the result of a longitudinal wave vibration can stimulate the sense of hearing.
What is a longitudinal wave?
waves are vibrations that propagate either through the medium of an intermediary or not. longitudinal wave is a wave that requires a medium to propagate.
always sound waves need a medium intermediaries in the propagation and airborne sound.
as evidence that sound waves
1. Guitar string in quotes
    guitar string in quotes will make the strings vibrate, the vibration that would arise from sound waves
2. Drums were beaten
when the drum in percussion drum causes the vibrational energy of the air particles around it vibrate follow drum vibration. then it was transferred to form the density and undensity in the air. if this wave to the human sense of hearing, there came the sound of drums before.
3. If you are in the vacuum we did not hear a sound.
while in the vacuum we would not be able to hear sounds at result that produced sound waves can not propagate so that the sound will not be heard or not up to the sense of hearing. This is evidence that the sound is a longitudinal wave.
because the sound is the sound waves possess the general properties of the wave
resonance, diffraction, reflection, refraction, and interference

Senin, 17 Desember 2012

how rainbows are formed?





Have you ever seen the rainbow? Beautiful is not it?
Have you ever noticed that the rainbow is a natural phenomenon that occurs with physical processes that are very interesting to learn. Here, then, will be described how paoses the rainbow. 
Rainbow is an arc spectrum which occurred due to refraction of sunlight by drops of water. The rainbow is an optical and meteorological phenomenon in the form of colorful light parallel to each other in the sky or other medium. In the sky, a rainbow appears as an arc light at the end leads to a time horizon of light rain. Rainbow can also be seen around a raging waterfall.
This occurs when the air is very hot but rain drizzle. We can see this phenomenon clearly, if we stand back to the sun. Rainbow can also be formed due to foggy or dewy air.
In physics, a rainbow can be explained as a natural refraction event. Refraction is the process diuraikannya a specific color to some other color (also called spectral colors), with a medium / medium well specified.
In the rainbow, color berurainya process occurs when white sunlight breaks down into a spectrum of colors with medium rain. The spectrum of colors that occur consist of red, orange, yellow, green, blue, indigo, and violet.
Rainbow phenomenon can also occur around the falls. Splash water around the falls as a medium to describe the color of the sunlight that shines.
 
Occurrence Process Rainbow
The sunlight is polychromatic light (made up of many colors). The white color of sunlight is actually a combination of various wavelengths of light with different. The human eye can perceive at least seven colors contained in sunlight, which will look at the rainbow: red, orange, yellow, green, blue, indigo, and violet.
The wavelength of light is forming ribbons parallel lines, each color shades of the color next to it. The tape is called a spectrum. In the spectrum, the red line has always been on one side and blue and purple on the other, and this is determined by the difference in wavelength.Rainbow arc spectrum is nothing that is happening because of the refraction of sunlight by drops of water. When sunlight through water droplets, such as when he refracted through a glass prism. So in a trickle of water, we've got different colors extending from one side to the other water droplets. Some of the colored light is then reflected from the far side of the water droplets, again and again out of the water droplets.
The light came back out of the water droplets in different directions, depending on the wavelength. Different wavelengths, will bring the colors of the rainbow are arranged with red top and purple on the bottom of the rainbow.
Rainbow can only be seen when the rain along with the sun shining, but from the opposite side to the viewer. The position of the observer must be between the sun and the water drops with the sun dibekalang person. The sun, the eye of the observer and the center of the arc rainbow shall be in a straight line.


 The cause of the refraction of light
 Refraction of light occurs when light passes from one medium to another with the propagation of different optical densities, changing speed and changing direction if not incident perpendicular to the surface. Refraction is the deviation in the direction of light propagation is described by Snell's law. Law and refraction in homogeneous media, is a consequence of Fermat's principle, which states that light travels between two points along the optical path requires a little more time.

In addition, the speed of light in a medium other than penetration associated with vacuum wavelength and, when a beam of white light passes from one medium to another, each color having a little deviation. This phenomenon is known as the scattering of light. For example, to achieve a solid medium, the wave loses speed on shorter term (eg, when white light passes through a prism). Shorter wavelengths are scattered up to 4 times during it which is why the sky looks blue because the color range for the index of refraction larger and more spread out.

In the law of refraction is Huygens concluded all control over the entire wave motion:

   1.  Rays incident, reflected and refracted are in the same plane.
   2. Angles of incidence and reflection are the same, which means they each incident and reflected beams perpendicular (called Normal) for the boundary drawn at the point of incidence.

picture a. shows water waves propagate from one medium into another medium to after passing the boundary between the two media, the wave is experiencing deflection. In the event of any change and the direction of wave propagation λ2 wavelengths shorter than λ1.
Figure (b) shows the change in wave speed. The wave propagates from a medium that has a refractive index n1 to another medium of refractive index n2
Description:
(a) The change in wavelength, λ2 shorter than λ1.
    b) Changes in wave velocity, v2 is smaller than v1.
The second image is derived from the refraction of the wave equation as follows:
sin i / sin r = v1/v2 =
(fλ1) / (fλ2) = λ1/λ2 
From one medium to another medium, the frequency of the wave remains. So that changes the speed and wavelength