Cocos2d-x start learning summary
Want to learn Cocos2d-x, because they can not prove that certain laws of physics in high school physics class, such as Ohm's law.
To this end, I read physics textbooks higher level, wherein on Ohm's law \ (R = \ frac {U } {I} \) proved substantially follows
The proton conductor metal is regarded as a rigid body relative to the stationary lattice configuration, the electron can be regarded as freely around the proton shuttle, from time to time be completely elastic collision and rigid protons.
When the conductor without an electric field, the electron is not inside the stationary conductor. Electronics are always in constant random thermal motion, occasionally collide with a proton lattice. In the absence of an external electric field or other reasons, the probability of their movement in either direction are the same. So from a macro point of view, random thermal motion of free electrons do not generate electricity.
When an electric field is added when the conductor, the movement of electrons by two parts: random thermal motion and directional movement under the action of an electric field. This can be considered the total velocity of electrons by the thermal motion of its speed and directional velocity generated by the electric field components. The former is an average vector of 0, which is called the average drift velocity, with \ (U \) is represented. This directional drift motion in the macroscopic form a macroscopic current.
Acceleration of free electrons in the electric field obtained is \ (A = - \ FRAC {m}} E {E \) . Due to the collision of protons, increasing the free electron orientation speed has been limited. After the collision of electron and proton scattering lattice what direction having a great chance. We can assume that the probability of scattering equal speed in each direction, i.e. completely lost at this time the electronic directional movement characterized in that the orientation speed \ (U_0 = 0 \) . Since electrons under the influence of an electric field forces from scratch uniformly accelerated motion. Before next collision, its orientation speed is obtained \ (U_1 = A \ bar \ of tau = - \ FRAC {m}} E {E \ bar \ of tau \) , where \ (\ bar \ tau \) is an electron in the mean time between two collisions free flight.
In a mean free path within the average drift velocity (average particle path length of each segment between two consecutive collisions that may be adopted) electrons \ (u = \ frac {u_0 + u_1} {2} = \ frac {1 {2}} (0- \ FRAC {m}} E {E \ bar \ of tau) = - \ FRAC {E} {E} 2M \ bar \ of tau \) .
Also, because \ (\ bar \ of tau = \ FRAC {\ bar \ the lambda} {\ bar V} \) , so \ (u = - \ frac { e} {2m} \ frac {\ bar \ lambda} {\ bar v} E \)
Do you still remember the expression of a constant current, we need to use it to launch \ (U \) and \ (I \) relations. Section taken perpendicular to the plane of the wire element \ (\ S of Delta \) . From a macro point of view, we can say that all electrons with the same speed \ (u \) movement. At time (Delta t \ \) \ internal electron moves through a distance \ (U \ of Delta T \) . In \ (\ Delta S \) a bottom, \ (U \ of Delta T \) is high for a cylinder, disposed conductor electron density is n, then this column body has \ (nu \ Delta t \ Delta S \) free electrons. In \ (\ Delta t \) time by \ (\ Delta S \) power is \ (\ of Delta Q = neu \ of Delta T \ of Delta S \) , then the \ (I = \ frac {\ Delta q} { \ Delta t} = neu \ Delta S \)
U on the front of this formula into Formula give \ (I = - \ frac { ne ^ 2} {2m} \ frac {\ bar \ lambda} {\ bar v} E = - \ frac {ne} { } 2M \ FRAC {\ bar \ the lambda {} \} the U-bar V \) . Because of \ (n, e, m, \ bar \ lambda \) in any case is constant, and \ (\ bar v \) at constant temperature is constant, the temperature unchanged \ ( \ frac {U} {I} \) unchanged.
Because of \ (\ frac {U} { I} \) at constant temperature constant, and at the same voltage, \ (\ frac {U} { I} \) larger, \ (the I \) smaller , i.e., the current conductor greater impediment, therefore \ (R = \ frac {U } {it} \) resistive conductors is referred to, showing the impediment current conductor.
- "The new concept of Physics, Electricity and Magnetism" p305 conductive metal classical electron theory
Along the particle can be abstracted into a rigid body perfectly elastic collision of ideas, I thought: Can this model be built up by cocos computer? If you really finished the project, to prove that it is not just simulation of Ohm's law, as well as the entire contents of the electrostatic field experiments and constant current physics elective 3-1.