c
Wednesday, January 30, 2008
d
A grade of 83. [partial daw]
It seems that it really has a great effect to me.I can't imagine a great of 83.
amf.
now I'm feeling it.
and I'm trying to get at least a grade of 85.
there can be miracles. [yak.haha]
It's Better To LEARN nothing than to KNOW nothing
lured into a deep sleep at Wednesday, January 30, 2008 0 person(s) commented while I sleep
lured into a deep sleep at Wednesday, January 30, 2008 0 person(s) commented while I sleep
Waaaa.
I think i'll be regereting what I've done.I haven't submitted any of the two projects.
And it makes me feel guilty.
waaaa.
It's Better To LEARN nothing than to KNOW nothing
lured into a deep sleep at Wednesday, January 30, 2008 1 person(s) commented while I sleep
lured into a deep sleep at Wednesday, January 30, 2008 1 person(s) commented while I sleep
Force
In physics, force is what causes a mass to accelerate. It may be experienced as a lift, a push, or a pull. The acceleration of the body is proportional to the vector sum of all forces acting on it (known as the net force or resultant force). In an extended body, force may also cause rotation, deformation, or an increase in pressure for the body.F = I * L * B
Where:
F=Force
I=Current
L=Length
B=Magnetic Field
In physics, the magnetic field is a field that permeates space and which exerts a magnetic force on moving electric charges and magnetic dipoles. Magnetic fields surround electric currents, magnetic dipoles, and changing electric fields.
Fleming's left hand rule
the use of right hand
Direction of force
The direction of force is determined by the above equations, in particular using the right-hand rule to evaluate the cross product. Equivalently, one can use Fleming's left hand rule for motion, current and polarity to determine the direction of any one of those from the other two, as seen in the example. It can also be remembered in the following way. The digits from the thumb to second finger indicate 'Force', 'B-field', and 'I(Current)' respectively, or F-B-I in short. Another similar trick is the right hand grip rule.
In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field (can also be equated to "Electric Flux Density"). This electric field exerts a force on other electrically charged objects. The concept of electric field was introduced by Michael Faraday.
Similarities between electrostatic and gravitational forces:
- Both act in a vacuum.
- Both are central and conservative.
- Both obey an inverse-square law (both are inversely proprotional to square of r).
- Both propagate with finite speed c.
- Differences between electrostatic and gravitational forces:
- Electrostatic forces are much greater than gravitational forces (by about 1036 times).
-Gravitational forces are attractive for like charges, whereas electrostatic forces are repulsive for like charges.
-There are no negative gravitational charges (no negative mass) while there are both positive and negative electric charges. This difference combined with previous implies that gravitational forces are always attractive, while electrostatic forces may be either attractive or repulsive.
- Electric charges are invariant under Lorentz transformations while gravitational charges (relativistic mass) are not.
It's Better To LEARN nothing than to KNOW nothing
lured into a deep sleep at Wednesday, January 30, 2008 1 person(s) commented while I sleep
lured into a deep sleep at Wednesday, January 30, 2008 1 person(s) commented while I sleep
Looking forward to a great 2008
oh. year 2007 was indeed a great year for me.excpt for one thing.
I wasn't able to pass the required projects for this subject.
And of course, it will deal a lot of damage to my grade in Physics.
I just want to forget those bad memories i have experience with this class.
Even though i frequently not undrstand what our teacher try to discuss but i still try my very best to be able to cope up with these lessons.
By this year 2008, may be the start of another fruitful year not just personally but also academically.
Happy new year!
It's Better To LEARN nothing than to KNOW nothing
lured into a deep sleep at Wednesday, January 30, 2008 0 person(s) commented while I sleep
lured into a deep sleep at Wednesday, January 30, 2008 0 person(s) commented while I sleep
c
Wednesday, October 24, 2007
d
Electric Field
Electric FieldIn physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field. This electric field exerts a force on other electrically charged objects. The concept of electric field was introduced by Michael Faraday.
The electric field is a vector field with SI units of newtons per coulomb (N C−1) or, equivalently, volts per meter (V m−1). The direction of the field at a point is defined by the direction of the electric force exerted on a positive test charge placed at that point. The strength of the field is defined by the ratio of the electric force on a charge at a point to the magnitude of the charge placed at that point. Electric fields contain electrical energy with energy density proportional to the square of the field intensity. The electric field is to charge as acceleration is to mass and force density is to volume.
A moving charge has not just an electric field but also a magnetic field, and in general the electric and magnetic fields are not completely separate phenomena; what one observer perceives as an electric field, another observer in a different frame of reference perceives as a mixture of electric and magnetic fields. For this reason, one speaks of "electromagnetism" or "electromagnetic fields." In quantum mechanics, disturbances in the electromagnetic fields are called photons, and the energy of photons is quantized.
A stationary charged particle in an electric field experiences a force proportional to its charge. The electric field is defined as the proportionality constant between charge and force in this relationship:
where F is the electric force on the particle, q is its charge, and E, is the electric field that the particle is in.
Electric Field Line
Electric field lines can be drawn using field lines. They are also called force lines.
(positive charge electric field)
The field lines are originated from the positive charge.
(negativ charge electric field)
The field lines end up at the negative charge.
A positive charge exerts out and a negative charge exerts in equally to all directions; it is symetric. Field lines are drawn to show the direction and strength of field. The closer the lines are, the stronger the force acts on an object. If the lines are further each other, the strength of force acting on a object is weaker.
It's Better To LEARN nothing than to KNOW nothing
lured into a deep sleep at Wednesday, October 24, 2007 0 person(s) commented while I sleep
lured into a deep sleep at Wednesday, October 24, 2007 0 person(s) commented while I sleep
c
Monday, October 15, 2007
d
potential energy
Potential EnergyAn object can store energy as the result of its position. For example, the heavy heavy ball of a demolition machine is storing energy when it is held at an elevated position. This stored energy of position is referred to as potential energy. Similarly, a drawn bow is able to store energy as the result of its position. When assuming its usual position (when not drawn), there is no energy stored in the bow. Yet when its position is altered from its usual equilibrium position, the bow is able to store energy by virtue of its position. This stored energy of position is referred to as potential energy. Potential energy is the stored energy of position possessed by an object.
Gravitational Potential Energy
Gravitational potential energy is the energy stored in an object as the result of its vertical position or height. The energy is stored as the result of the gravitational attraction of the Earth for the object. The gravitational potential energy of the massive ball of a demolition machine is dependent on two variables - the mass of the ball and the height to which it is raised. There is a direct relation between gravitational potential energy and the mass of an object. More massive objects have greater gravitational potential energy. There is also a direct relation between gravitational potential energy and the height of an object. The higher that an object is elevated, the greater the gravitational potential energy. These relationships are expressed by the following equation:
PEgrav = m * g * h
m represents the mass of the object, h represents the height of the object and g represents the acceleration of gravity (9.8 m/s/s on Earth).
Elastic Potential Energy
Elastic potential energy is the energy stored in elastic materials as the result of their stretching or compressing. Elastic potential energy can be stored in rubber bands, bungee chords, trampolines, springs, an arrow drawn into a bow, etc. The amount of elastic potential energy stored in such a device is related to the amount of stretch of the device - the more stretch, the more stored energy.
Springs are a special instance of a device which can store elastic potential energy due to either compression or stretching. A force is required to compress a spring; the more compression there is, the more force which is required to compress it further. For certain springs, the amount of force is directly proportional to the amount of stretch or compression (x); the constant of proportionality is known as the spring constant (k).
If a spring is not stretched or compressed, then there is no elastic potential energy stored in it. The spring is said to be at its equilibrium position. The equilibrium position is the position that the spring naturally assumes when there is no force applied to it. In terms of potential energy, the equilibrium position could be called the zero-potential energy position. There is a special equation for springs which relates the amount of elastic potential energy to the amount of stretch (or compression) and the spring constant. The equation is
Summary:
potential energy is the energy which is stored in an object due to its position relative to some zero position. An object possesses gravitational potential energy if it is positioned at a height above (or below) the zero height. An object possesses elastic potential energy if it is at a position on an elastic medium other than the equilibrium position.
It's Better To LEARN nothing than to KNOW nothing
resistors
Bad Beers Rip Our Young Guts But Vinta Gives Well.
A resistor is a two-terminal electrical or electronic component that resists an electric current by producing a voltage drop between its terminals in accordance with Ohm's law: R= V/I .The electrical resistance is equal to the voltage drop across the resistor divided by the current through the resistor. Resistors are used as part of electrical networks and electronic circuits.
Working with very imprecise measurements, Ohm was able to determine that voltage and current for any fixed geometrical structure built from conducting material satisfied a relationship:
V = I R
where:
V is the voltage across the device,
I is the current flowing through the device,
R is a constant.
R depends upon the material from which the device is constructed and the geometry of the material.
It's Better To LEARN nothing than to KNOW nothing
lured into a deep sleep at Monday, October 15, 2007 0 person(s) commented while I sleep
lured into a deep sleep at Monday, October 15, 2007 0 person(s) commented while I sleep