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TUGAS UAS

Nama : Rahmi Hartinah
NIM : RSA1C311014
Pend. Fisika PGSBI 2011

1. ) Kinetic energy is energy owned by any object when it is moving. For example, people running, a car running in medium speed, rotating object, moving cart, and billiard. When moving, objects have energy. Because kinetic energy is owned by moving object, the value of energy is depended on mass and velocity.

In my report is about billiard. In billiard, we often see a ball hit using stick will move and hit the other ball. What happens with the ball? In fact, the ball also moves because of the motion of the first ball. This means that moving ball is able to do work or has energy. The energy is called kinetic energy. Value kinetic energy of any object is depending on it mass and speed. The formula is :

Ek = _½ mv²

Ek : Kinetic Energy (Joule)

m : mass of oject (kg)

v : velocity of any object (m/s)

For example :

An object has 70 kg of mass and is moving with 6 m/s of speed. Calculate the kinetic energy.

Solution:

Known : m = 70 kg

               V = 6 m/s

Question : Ek = ….. ?

Answer : Ek = _½ mv²

                               ⁼  _{½ x 70kg} x (6 m/s)²

                       = 1260 Joule

Thus, the kinetic energy of the object is 1260 Joule.

Based on the example above, it was concluode that to perform its work, energy is needed. Until nowadays, there is no instrument that can produce energy without deriving energy from outside. This means, energy can not be created, only altered to the other form of energy. The statement above is known as conservation laws of energy.

2 ) Look at the experiment about Pendulum..

Ok, let see…

1.      Prepare all the material (such as a pendulum with weight of 100 grams, thread about 150 cm, a prop, a stopwatch)

2.      Tie the pendulum with the thread and hang it on the prop

3.      Swing the pendulum with oscillation deviation (amplitude) of 10⁰  

4.      Write the time of 10 oscillations. How long does it take ?

5.      Repeat the experiment by changing the amplitude (not more than 15⁰   )

For the experiment, we get the concluded as follow, even if the amplitudes are different, it turns out that 10 times oscillations need the same amount of time, the time needed to do one oscillation (period) of different amplitudes turns out to be the same.

So, the time of a period does not depend on the amplitude but on the number of oscillations in one unit of time.

3 )Electricity is the flow electrons from atom to atom in a conductor. All atoms have a particles call electrons located in orbit around a proton.

Ohm’s law is “ the amount of current strength (I) through a conductor between two points is proportional to the potential difference or voltage (V) at two points, and inversely to the resistance (R)”.

The formula electricity is :

I = V / R

The problem:

In the one battery, the voltage is 1,5 V. and connected to electricity with the current is 15 A.

How much the value for Resistance?

Solution :

Know : V = 1,5 V

               I = 15 A

Question : R = ……?

Answer : I = V / R

So,                   15 A = 1,5 V / R

                        R = 1,5 V / 15A

                        R = 0.1 Ohm

 4 )

Sound as a wave

In our daily life, we always produce sounds. Musical sound, motorize vehicle sound, or the sound your produce when communicating with other person are examples of sounds. There are loud hear able sounds, there are also weak hear able sounds, and nice to listen hear able sounds. Because human hearing is limited, there are sounds we can hear and there are also sounds we cannot hear.

Sound has characteristic, such as it originated from an oscillating object, it propagates through air in the form of a longitudinal wave, it need a medium to propagate, and it reflects if it hits a barrier wall. So, as a mechanic wave, sound can only propagate through a medium.

Sound can be heard if there are three factors, which are sound source, medium, and listener. Sound source is anything that can produce sound. Loudness of sound depends on amplitude, oscillation, and distance from sound source to the listener.

The sound wav can be heard if there is a medium for propagating from the source to the listener. The sound you hear is usually from a source which propagates through air. In vacuum space, sound wave cannot propagate so the sound produce cannot be heard.

So, the conclude is sound is a result of an oscillating object and sound is wave depended to sound source, medium, and listener. If there is no medium, we cannot hear a sound.

physics in our daily life

Many people assume that just Physical science which only naturalize without any implementation. Mainly there are still many people who think that the only study physics formulas. And not a few who do not realize that many of the events even things that are very close to us involves the science of Physics. Even Physics is the basic science that is needed by the other branches of sciences. Why Physics is very important in our lives?
Of course as many of the events in our lives that involve science Physics whether we realize it or without us knowing.

Look at the picture !

Two students were carrying the chair. Only push and pull them. Working together they cause the seat can be moved easily. Similarly, the force required to kick the ball so that the ball right up to the specified target.

Pull or push in physics called the force. Thus, the work force on an object is synonymous with pushing or pulling objects.

Two Kinds of Force :
There are two types of Force, the style of touch and Force not touch.
1. Force touch
Touch Force is a force that arise due to direct physical contiguity between two objects.
Examples of touch force: friction, normal force, the spring force, muscle force and the like.

2. Force does not touch
Do not touch force is a force that does not arise even if the two objects rub together physically.
Examples of force not touch: the gravitational force, magnetic and electric force.

and, the formula the force is :

• F : force (N)
• m : mass (kg atau g)
• a : acceleration (m/s² atau cm/s²)

if the mass is increase, so the force is increase too and the greater the force applied the greater the acceleration experienced by the object.

The Waves

Based on the propagation medium, the waves are grouped into two, namely mechanical waves and electromagnetic waves. Mechanical wave is a wave that requires a medium in the propagation. Among other examples of mechanical waves: sound waves, surface waves, and the waves on a string. Electromagnetic waves are waves that do not require the propagation medium. Example: light, radio waves, TV waves, X - rays, and gamma rays.
The wave is due to the merambat.Menurut perturbed physics concept, reflection wave propagation is perturbed, while the medium remains. Thus, a wave propagation without energy transfer followed by removal of the mass media.

A. Definition of Wave Mechanics
Mechanical wave is a wave that requires a medium in propagation.
Examples of mechanical waves:
- The waves that occur on the string if one end digerak move.

- The waves that occur on the surface of the water if given perturbed him (eg by dropping rocks on the surface of a quiet pond water).

B. Transverse waves
Transverse waves are waves that knock the direction perpendicular to the vibration direction (harassment).
Examples of transverse waves:
- Vibration learned gitas ray
- Vibrations shake the rope at one end


C. Longitudinal Waves

Longitudinal waves are waves that knock the direction parallel to the direction of vibration (direction of harassment)
Examples of longitudinal waves:
- Wave slinki tied at both ends to the stative then given perturbed at one end
- Sound waves in air

Wavelength
One wave length equal to the distance traveled in one period.
1) The wavelength of the transverse wave
In transverse waves, the wave consists of 3 vertices and 2 stomach. The distance between two nodes or two successive stomach is called a half or ½ wavelength λ (lambda),
2) The wavelength of the longitudinal wave

In the longitudinal wave, 1 wave consists of 1 density and 1 strain 

The distance traveled by the wave in one second is called the wave propagation speed. Wave propagation speed is denoted by v and the unit m / s . The relationship between v, f, λ, and T are as follows:

Description:
λ = wavelength, units meters (m)
v = velocity of wave propagation, units meters / second
T = wave period, units of seconds or seconds (s)
f = frequency of the wave, or 1/second 1/second unit


Example Problem:
1. Waves generated in 1 second as shown below:

a. what is the frequency of the wave?
b. When the distance PQ = 2 cm, then what is?

Completion:
According to the images, which occur as the wave 2 wave. Means, f = 2 wave / second or f = 2 Hz.
In figure 2 wave occurs (2λ). So 2 λ = 2 cm, or λ = 1 cm.

2. A rope stretched 8 m in length and vibrated. During the 2 second wave occurred as shown below! Define λ, f, T, and v.

Completion:
from the picture, wave of as many as 4 λ.
Means: 4λ = 8 m so λ = 8/4 = 2 m
During the 2 second occurred four λ or for 1 second occurred 2λ
Thus, f = 2 wave / second or f = 2 Hz
T = 1 / f = ½ second so that v = λ f = 2 m x 2 Hz = 4 m/s

Playing with magnet..

oke guys,
now, I want to give you a game..
in here, we need :
1. steel needle
2. sewing thread 30 cm,
3. tissue
4. bar magnet, and
5. scissors

we must do :
1. Cut tissue paper and create a wing length of about 2.5 cm
2. Stick a needle through the middle of the wing to make the paper "airplane".
3. Tie a piece of yarn on the needle.
4. Put a magnet on the table with the tip protruding beyond the sides of the magnet on the table.
5. Attach the aircraft at the end of the magnet.
6. Pull the thread slowly, until the plane flying through the air.

and the result is the airplane, still flying in the air if still near to magnet.

why it can be happened?

The strength of the attraction between the two magnets depends on how regularity "magnetic force" (a group of atoms that act like tiny atoms) in the second magnet. Before affixed to a magnet, the atoms are not arranged in a regular needle. The number of atoms that arrange themselves into groups and marched in the needle during needle attached depends on the strength of the magnet.
Both needles and magnets have magnetic properties. Their attraction to the style that is large enough to overcome the downward pull by gravity, which allows the aircraft to fly fixed float.

ok friends..
happy try it..







Reference:
http://www.arianto.net/index.php?option=com_content&view=article&id=21:pesawat-terbang-melayang&catid=2:magnet&Itemid=9

make a light with a ballon

A ballon can produce a light.
how to make it?

oke guys, we need some materials:
1. A ballon
2. Neon light or tube light.

and the procedure :
1. Blow up a balloon, and then bunch.
2. Washing the outside of the lamp, and dry.
3. In a dark room, place one end of the neon lights on the floor.
4. Hold and stand up neon light.
5. Rub the balloon up and down rapidly on the surface of the tube.
6. Hold, and bring to neon light.
7. Neon lights begin to flicker and the light moves to follow the movement of the balloon.

Just by hovering balloons with lamp can be generated light.
Why it happened?

If the tubes are connected to an electrical current, chemicals in very fine filaments at the ends of the tubes are releasing electrons. Electrons jump from one end to the other lights, producing 120 flashes per second. Because the flash is too fast, ultra violet rays are not visible to the human eye. A drop of mercury in the tube lights flash vaporized by electricity, and the steam carries the electrons toward the phosphor powder coating on the inner wall of the tube. The layer converts the energy into energy ultra violet light that can be seen.

Rub a balloon on the tube causes a similar change occurred, but in a smaller size. Rubbing causes electrons gather on the surface of the balloon. Accumulate electrons that cause the mercury vapor inside the tube to be charged, and as if the tube is connected to an electric current, charged mercury vapor chemicals mashing to incandescent, producing visible light.

now,, you can try it at your home..






Reference :
http://www.arianto.net/index.php?option=com_content&view=article&id=2:nyala&catid=1:listrik&Itemid=9

DRUG ABUSE !!!!!!!!!!!

When considering, "what is drug abuse?" one should remember drug abuse is not the same thing as drug dependence or drug addiction. Drug dependence or addiction indicates a psychological or physical dependence on the drug to function. Drug dependence requires the symptoms of withdrawal if the drug is discontinued, where as drug abuse does not. The National Institute on Drug Abuse indicates the following risk factors for developing drug abuse problems (typically seen in adolescence):2 1. Unstable home environment, often due to drug abuse or mental illness of the parent 2. Poor relationship with parents 3. Inadequate supervision over adolescent's activities 4. Use of drugs by friends / peers 5. Permissive attitude towards their own drug use and the drug use of the adolescent 6. Behavioral problems combined with poor parenting 7. Poor achievement in school, etc. Effect of Drug Abuse on the Body A person who abuses drugs may not realize they have a problem until pronounced effects of drug abuse are seen, often physically. While drug abuse effects on the body vary depending on the drug used, all drug abuse negatively impacts one's health. Common effects of drug abuse on the body include sleep changes and decreased memory and cognitive abilities. Other common physical problems include:1 2 1. Abnormal vital signs like respiration, heart rate and blood pressure 2. Chest or lung pain 3. Nausea, vomiting, diarrhea, stomach pain 4. Skin can be cool and sweating or hot and dry 5. Diseases such as hepatitis B or C, or HIV from needle-sharing 6. Impotence 7. More frequent illnesses 8. Frequent hangovers, blackouts Psychological Drug Abuse Effects One of the primary effects of drug abuse can be found within the definition of drug abuse itself: an increasing, intense desire to use the drug above all else. Drug craving can shift a person's entire mental focus to obtaining the drug. Side effects of drug abuse then include preoccupation with where to get the drug, how to get money for the drug, and where and when the drug can be used. Psychological drug abuse effects commonly include changes in mood. A person may be anxious, thinking about when they can next use the drug, or depressed due to drug side effects. Other psychological drug abuse side effects include: 1. Aggressiveness or irritability 2. Selfishness 3. Hopelessness 4. Lack of pleasure from previously enjoyed activities 5. Pressuring others into doing drugs and now, say no to drugs... love your body. . . REFERENCE: http://www.healthyplace.com/addictions/drug-addiction