Work Heat and Internal Enegi

a. System and Environment
A system is part of the universe wich becomes the attention of an observation. While the environment is other part of the universe which is separated from the system. Examples of a system we can see in daily life is helium gas cylinder and ga balloon.




If we are only observing the helium gas tube, than the tube becomes the boundary between, the system and its outside emviroment.
Otherwise if we are only observing the balloon, then the surface of the balloon becomes the boundary between the system and its outside environment.

b.Work
Work is the amount of energy transferred from the system to its environment o vice versa.

c.Heat
Heat is the amount of energy transferred from the system to its environment resulting from the temperature difference.

d.Internal energy
Internal energy is the sum of the kinetic and potential energies of all the atoms or moleculs of substance.



Work                                Heat                          Internal energy

Since it is microscopic, than what we can observe macroscopically is the conversion of the internal energy ΔU of the substance. If the system changes from initial state U1 into final state U2, then the change of internal energy is  :

    ΔU = U2 –U1

TIDE physics edu

physics in the article today, I elaborated on the tide

A tide is the periodic rice and fall of the sea surface.
Tide result from the gravitational attraction of the moon.

The principal couse of tide is the moon being much nearer to the earth then the sun so that the world’s oceans flow in response to the moon’s pull.

Because the moon moves around the earth, the highest high tide and the lowest high tide can occur.

a. The highest high tide if the Eart, Moon and Sun are in the same line (if seen from North). The highest hige tide is often called luna tide.

b. The lowest high tide accurs if Eart, Moon and Sun make a right angle (90o). the lower high tide is often called a quarter tide.

Fundamental Quantities

Something can be measure and expressed by a value is called quantity, and generally it a unit.

A quantity use in science and tecnologi is a call a phisicall quantity.
Examples of physical quantities length, weight and time.

Ekample :

1.What quantity is being measure by this boy ?

2.What quantity is being measure by this man?

3.What quantity is being measure by this woman ?

4.What quantity is being measure by this man ?

The seven of fundamental unit of the International System

Fundamental Quantities	unit	abbreviation	dimension
Length	meter	m	L
Mass	kilogram	kg	M
Time	second	s	T
Temperature	kelvin	K	θ
Amount of substance	mol	mol	N
Luminous intensity	candela	cd	J
Electric current	ampere	A	I

Very large or very small numbers are difficult to express such as the earth’s radius or time between collisions in SI units.

So to make it simple, we use a prefix.

prefix	abbreviatin	factor
exa	E	1018
peta	P	1016
tera	T	1012
giga	G	109
mega	M	106
kilo	k	103
hekto	h	102
deka	da	10

Law of Love Monkey

Now let us study the Coulomb's law with the love parable teenagers (ABG), we call this law Law of Love Monkey let me not scary anymore with the physics lesson, or let me not boring anymore. But this is actually a method that does not theorize, but proven to be remembered forever by my students in high school.

Suppose that:

A is a high school kid, girl, gorgeous, rich, humorous, outgoing, caring, etc..
B is a high school kid, girl, gorgeous, smart, sociable, attentive, helpful if you see his friend in trouble.
C is a high school kid, male, handsome, often oversleep klo school, lazy, idol girls in high school because good music playing.



One day C invented by A, then there was an intimate love relationship romance. The C into the spirit entered his school, which usually come at 8 am, now five in the morning was perched at the school .... Hahaha! The power of love C of A is very large because in addition to falling within the scope of the SMA, A is also beautiful, humorous, wealthy, and attention at all.
One day their love story known to the parents of A, A worried parent learning activity is interrupted, so he moved his school to another school. Because the distance between school C with school A not so distant and so strong his love, now C back to its original habit, always late and lazy, but he was more active presence in the school veranda A.
A romantic relationship with C is found again by the parents of A, and the parents decided to send their A A overseas. Meranalah then the C, behavior begun to be lazy, now with a further distance away.
Looking at C is always moody, B feels pity, he approached, he advise, "be patient, when it certainly met her match again" he said. Attention B to C is so sincere and felt very encouraging for C. Begin arise affection for B, and C started working again to school, learning spirit re-emerged. Because of the distance A to C is very far away, love C of A begins to wear off. Moreover, there is now concern that were located very close to B to C. C then decided to establish in love with B. Shoots be loved side dish arrived, finally going with B. C
Well, if we suppose that A and B is a negative charge, C positive charge. According to Coulomb's Law states that "style attraction / repulsion between two charges declined proportional to the charge itself and berbading kuwadrat inversely with the distance between the two charges are" (Note: If the two charges were different types of attractive forces will occur, if the two charges together kind then there is a repulsive force declined).
So A and C will have the attractive forces (power of love) is very strong when the distance is relatively close, while the distance in the gravity pull away (ideal strength) will be weakened. When A and B away closer to C then the attractive forces between B and C will be stronger than attractive forces between A and C.
Mathematically formulated Coulomb's Law:

F = k (q1. Q2) / r ^ 2

q1 & q2 = charge,
r = distance between two charges,
k = dielectric constant, and
F = the Coulomb

Resultan Vektor

Resultan Vektor

for high school physics ( Fisika sma smk )

When we train inside and outside of heavy rain, then we looked out the window. We see rain droplets fall sideways out there.
Why is that? This is caused by the existence of two movements moving in different directions.
1. The train moves horizontally with a speed νa.
2. Precipitation that falls perpendicular to the surface of the earth at νb.
If the two vectors that we put down at one point arrested then we will get the sum of the second vector is as below:

a = νa = speed of train
-a = - νa = velocity of the earth relative to the passenger
b = νb = velocity of the earth's rain
νc = c = speed of the rain relative to the passenger


From the description above it is clear that we see slanting rain outside the train isthe result of the resultant / sum of two vectors is the speed of the train velocity vectorand velocity vector rainwater  mutually perpendicular. The second resultant velocity vector is called the relative velocity of rain on us as a passenger train.

Note:
- The vector is a quantity that has a value and direction
- a = - νa, is actually the body's movement speed passenger who pushed back due to the speed of the train movement
for high school physics

Process of Sonic Boom

 Continued from physics lessons Doppler Effect 2

Process of Sonic Boom

F/A-18 Hornet flies at low heightof high  velocity. When is velocity reaches mach 1, a wall vapour around the airplane is formed.

The illustration above represents the sound wave fronts generated by an airplane moving with the same velocity as the sound wave.

The blue points in this illustration are the position of airplane when it emits the sound wave. As the speed of the source is the same as the velocity of the airplane, the sound wave of the point will accumulate and interfere in point. At this point many compressions will be found. As a result the air density at the point is very hight (as well its air pressure).
In order to move faster than the sound wave, the airplane should break throught the barrier of high air pressure.

Sound wave with the veri high amplitude will be heard as an explosion. Although it occurs verry short baut its vibration can break the window’s glass.
This explosion is called sonic boom.
Sometimes people misunderstand about this concept.
They assume that the explosion heard when supersonic airplane flies over them is because it is passing througt a barrier of high air pressure.


 File Process of Sonic Boom
physics education  physics lessons Doppler Effect 2 Process of Sonic Boom for high school

Doppler Effect 2

Continued from Doppler Effect 

If moves away from the source, then the wave received is less so that its frequency is lower. The formula for its frequency is :  

f’ = {(ν – ν_p)/ν}f

The conclusion of Doppler Effect :

a.       Source is in motion :

      Source approaches : use (-) sign (frequency is higher)

Source approaches : use (+) sign (frequency is lower)

b.      Observer is motion :

      Observer apppraeches : use (+) sign (frquency is higher)

Observer moves away : use (-) sign (frequency is lower)

moving sound sources in the circuit

shock wave frequency chart
ν = the sound speed
νs = the source relative speed to the observer
 f = the source frequency
f’ = the frequency heard by the observer            


continued >>> Doppler Effect
The next physics lesson on the process of Sonic Boom
Doppler Effect
Physics education for High School

Mathematics physics education

Determining average velocity of fungtion of position

Average velocity (v) of a car can be calculated by dividing the displacement (∆r) by the time interval (∆t) taken :

• Instantaneous velocity (ν) of particle can be calculated from the average velocity with a small interval of time
• In calculus, the derivate of this equation is easer and can be written as : 
• So, the instantaneous velocity is the derivative of the position function :
• In mathematics, the derivative of function   

complete file Mathematics
physics education for High School
Mathematics physics education

Ridge Forge

Why the helicopter tilted position while on the move ?

Whatever force happens to helicopter ?

Note the picture beside.
When ignited aircraft  engine,  propeller  plane spinning but still not flying.
This is due to the gravity of the aircraft is still greater than ridge force, so theresultant  force of gravity in the direction of the helicopter..
Force that occurs in helicopter is:
a. F = force ridge, the force due to rotation speed 
     of the propeller
b. W = weight of the helicopter force, force due to
     entire mass of the helicopter due to the   
     influence of gravity earth
c. R = resultant force, the force of the sum / difference  between ridgepole  with  gravity force helicopter
If the ridge force greater than gravity object, then the heli will lift up the plane.

Resultant from ridgepole style propeller with gravity is what will determine thehelicopter moves fig.

Physics education Ridge Forge for High School
update 2012

video physics Movement Parabola

Movement Parabola

video physics lessons learning physics online website for high school
Movement Parabola

Doppler Effect

physics lessons Doppler Effect

When we are on a car circuit, we see that when a race car F1 approaches, its sound’s pitch is higher and when it travels away, its sound’s pitch is lower.
What is this ?
This is due to the shift in frequency and wavelength of waves or called Doppler Effect.
The frequency heard by an observer is higher when the source approaches the observer and lower when the source moves away from the observer.

How do we explain this Doppler effect ?
when the race car is at rest : Theconcentric circles illustrate the peak of wave. The distance between twoo circles equals the wavelength of sound. Here the wave received per second by the observer equals the number of waves emitted per second.

When the race car moves : Now the circles are not concentic anymore  and the observer in the front of the car will receive more waves per second (frequency received higher). Conversely the observer behind the car will receive fewer waves per second (frequency received is lower)                                                                       

The Frequency Doppler Effect also occurs when the observer approaches or moves 

If the observer approaches the source with the velocity vp, then the observer will receive more waves so that its frequency is higher. The formula for the frequency is : 

f’ = {(ν +ν_p)/ν}f

To file complete    Doppler Effect

Physics education High School physics lessons Doppler Effect

Kinematics

Particle’s Motion Kinematics
(Part 1)

Position, Displacement, and Distance
a. Position

Position is the location of particle relative to a frame of reference and expressed by te vector quantity r.

To exprexx directioan in a Cartesian coordinate, we us a unit vector perpendikular to each other.

Unit vector i ( in x direction), and

Unit vector j (in y direction)

If the particle or object is at point (x, y), then its position is expressed as:   r = xi + yj

b. Displacement

Displacement is the change in position of particle expressed as a vector quantity ∆r.

If r0 is the initial position and rt is the final position, then the displacement can be written mathematically as

r_o + ∆r = r_t

∆r = r_t – r_o

or

∆r = ∆xi + ∆yj 

c.      Distance 

Distance is the magnitude of displacement traveled 

by a particle as scalar quantity I ∆r I or ∆r.

Distance can be written matematically using Pythagoras’ theorem

Complete file Kinematics 
for High School