Semester Final Examination

Semester Final Examination

Name              : Oktaria Dwi Putri

NIM                 : RSA1C311009

Study Program            : Physics

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 

Around my house a lot of kids and when they play they saw palm trees in front of my house one of them asked his friend to get it for the coconut fruit. One of his friends had climbed to above pohin and when he dropped the coconut fruit. So, when the coconut fruit. So when the coconuts that fall occurs is the kinetic energy at the coconut fruit

Any moving object exerts a force on another object and move it as far as a certain distance. Moving objects have the ability to do work, therefore can be said to have energy. Energy on a moving object is called kinetic energy. The word comes from the Greek kinetic, kinetikos, which means "movement". when a moving object, the object must have speed. Thus, we can conclude that the kinetic energy is the energy possessed by the object movement or speed.

The formula is : Kinetic= KE= 1/2 MV^2 

m= mass,

 v= velocity

The energy of a body is a measure of the body's ability to conduct a business. Unit of energy is the joule. One of them is  Kinetic energy or energy of motion (also called kinetic energy) is the energy possessed by an object due to its motion.

Example :

1.      A soccer ball kicked by a mass of 150 grams of Ronaldo and the ball is moving straight toward the goal with a rate of 30 m / s. Compute:
a) The kinetic energy of the ball

my answer:

a) kinetic energy ball

KE = ½ mv2 = ½ (0.15 kg) (30 m/s2) 2 = 67.5 Joules

2.      A. An object with mass 0.5 kg falls from a height of 4m to the ground, if g = 10 m/s2, compute:

1. potential energy when drifting down
2. Kinetic energy when it hits the ground

Answer:
Given:
m = o, 5 kg
h = 4m
g = 10 m/s2



Answer:

1. potential energy when drifting down

      EP = M.G.H
0.5 kg. 4 m. 10 m/s2
= 20 A
2. Kinetic energy when it hits the ground

Due to mechanical energy = constant

That is: When it hits the ground there is no high
when it falls there is no velocity

EK formula: 1/2. M. V2

So 1/2. 0.5. 0

Any multiplied by zero, zero bound
EK = 0

So,  Kinetic energy of an object equal to the amount of effort required to express the speed and rotation, starting from the break.
Every moving object has energy. The energy possessed by a moving object is called kinetic energy. Or simply language: kinetic energy is energy that is being done on a moving object.
Kinetic energy of an object is defined as the effort required to move an object with a given mass from rest to reach a certain speed.

2 .   Describe an experiment which associated with the following terms : pendulum, frictional force and  highest point, then enter the terms into the procedures so that these terms included in your experiment.

Simple harmonic motion is the motion back - behind the object through a certain equilibrium point with the number of vibrations per second object is always constant. Simple Harmonic Motion can be divided into two parts, namely (1) Simple Harmonic Motion (GHS) Linear, such as vacuum gas in the cylinder, the oscillation motion of the mercury / water in the pipe U, motion horizontal / vertical springs, etc., (2) Simple Harmonic motion (GHS) angular, eg pendulum movement / physical pendulum, oscillating swing torque, and so on. The study of sound and vibration closely related can not be separated even by study of the swing or also called oscillation. This phenomenon in our daily life example is the movement of the pendulum clock, the mass movement which hung on the spring, and even the movement of the guitar strings when plucked. All three are examples of so-called swing. Then we come to determine percerpatan garavitasi earth (g) the mathematical pendulum

EQUIPMENT AND MATERIALS  
1. tool
• Swing mathematical consisting of
- Worsted Yarn
- Iron pejat the berkatrol
- Close the bottle
• Static Buffer
• Stop watch
• Rule 100 cm
• Bows

EXPERIMENTAL PROCEDURE
a) Provide a means to experiment.
b) Measure the length of rope hanging from the center of a ball point ± 90 cm.
c) Then measure the angle deviation of ± 150 to 200 balls and then removed.
d) Record time for 12 swings by pressing the stop watch when the pendulum is released and did 3X
e) Repeat the procedure 4 for a long string of 70.60, and 55
f) Make a table of the results obtained

CONCLUSION
That basically is the force of gravity caused the earth and can be calculated in various ways such as by simple pendulum swing. In simple pendulum swings the pendulum mass is not taken into account, that counts only the square of the period (T2) and a length of rope (R).
From the experiments we have done by using ropes and weights. We can deduce the effect of changes in the period of vibration is very powerful because if the length of the string that is used is shorter in the time needed to calculate the pendulum swing a bit more and vice versa.
In this experiment should be repeated SCARA, because if you only do a one-time experiment, the level of accuracy will be reduced. And while it is evaluated the weight and length of the eye we should be more cautious and alert when determining the time on the stopwatch.

3.      Make a simple calculation about electrical using the formula your well known. Write down your solution, and explain it by using your sentence ( change the number or symbol into your own word )

An important aspect of any electrical or electronic circuit is the power associated with it. It is found that when a current flows through a resistor, electrical energy is converted into heat. This fact is used by electrical heaters which consist of a resistor through which current flows. Light bulbs use the same principle, heating the element up so that it glows white hot and produces light. At other times much smaller resistors and very much smaller currents are used. Here the amount of heat generated may be very small. However if some current flows then some heat is generated. In this instance the heat generated represents the amount of electrical power being dissipated.

Unit of electric power

The unit of power is the watt which is often denoted by the symbol W. A typical light bulb may consume 60 watts of power. A domestic electric heater may consume a thousand watts or a kilowatt (kW). Even higher power levels are measured in Megawatts (MW) or millions of watts.

At the other end of the scale powers below a watt are commonly used. A milli watt (mW) means a thousandth of a watt, and a microwatt is a millionth of a watt.

How to calculate the electric power?

The amount of power dissipated in a circuit can be easily determined. It is simply the product of the potential difference or voltage across the particular element, multiplied by the current flowing through it. In other words an electrical fire running from a 250 volt supply, and consuming 4 amps of current will dissipate 250 x 4 = 1000 watts or 1 kilowatt. In other words.

W = V  x  I

W = total amount of power, in watts
V = operating voltage or potential difference, in volts
I =  actual current flowing through the device, in amps

In some instances the actual resistance of the circuit element may be known. By using Ohm’s Law ( V = I x R) it is possible to calculate the power if either the voltage or current is known. For example the mains voltage may be known to be 250 volts and the element resistance may be known to be 62.5 Ohms.

By performing some simple algebra it is possible to discover the very useful formulae:

W = V²/R

and

W = I² x R

Example :

1.      Using these formulae it is simple to work out the power dissipated in the 62.5 ohm resistor when a voltage of 250 volts is placed across it.

Known             :  R = 62.5 ohm V= 250 volts 

Ask                   : W?

Answer            : W = V²/R

Solution           :  W = V²

                               = 250 volts²  / 62.5 ohm

                              = 1000 volts/ ohm

4.      Make an essay about sound as a wave. Then show at least three evidence and examplifying about it.

Before we make essay about sound as a wave, we must know what is sound and wave?

The sound is normal mechanical vibrations that move through matter as a wave form. It consists of a longitudinal or compression waves in matter.
The waves are vibrations that propagate.

Characteristics of sound
Sound waves have the same characteristics as other types of waveforms. and amplitude. Has a wavelength, frequency, speed and amplitude.

Wavelength
Wavelength is the distance from one another crest of the wave. Since sound is a compression wave, the wavelength is the distance between the maximum compression.
Speed ​​or velocity
Sound waves move at about 344 meters / sec, 1130 ft / sec. or 770 miles per hour in a room temperature of 20 o C (70 o F).

Frequency
Frequency is the rate at which the sound waves pass a given point. It is also the rate at which a guitar string vibrates or speakers.
The relationship between speed, wavelength and frequency is:
velocity = wavelength x frequency

Amplitude
Since sound is a compression wave, amplitude according to how many waves are compressed, compared to the compression a little .. Therefore, it is sometimes called the pressure amplitude.

The sound of the waves have properties similar to the properties of the wave are:

a. Can be reflected (reflection)
Reflected sound can occur when sound on hard surfaces, such as the surface of the stone walls, cement, steel, glass and zinc.
example:
- Our voices were louder in the cave due to the reflection of sound on the wall of the cave.
- Our voices inside the building or music studio that does not use a silencer
.
b. Can be refracted (refiaksi)
Refiaksi linatasan wave is slue direction after passing the boundary between two different media.
Example: At night the sound of thunder sounded louder than during the day because of the refraction of sound waves.

c. Can be combined (interference)
Just as light interference, interference noise also requires two coherent sources of sound.
Example: Two loudspeakers are connected to a signal generator (audio frequency generators) can serve as two coherent sources of sound.

d. Can be bent (diffracted)
Diffraction is flexing event sound waves when passing through a narrow slit.
Example: We can hear the sound of the room of different and closed, because the sound through narrow slits that are passable sound.

So, Sound consists of longitudinal or compression waves that moves through air or other materials. He does not travel in a vacuum. The sound has a characteristic wavelength, frequency, speed and amplitude. Sound waves will be created by the vibration of some object and detected when they cause the detector to vibrate.