Summary?
Physical theorems, laws, formulas?
One,
(1)- linear motion?
1) even number
1.
V flat = s/t (definition)? 2. Useful inference VT2-VO2 = 2as?
3. Intermediate speed vt/2 = Vping = (vt+VO)/2? 4. terminal speed vt = VO+at?
5. Intermediate position speed vs/2 = [(VO2+VT2)/2] 1/2? 6. Displacement S = V level T = VOT+AT2/2 = vt/2t?
7. acceleration a = (vt-VO)/t? {With Vo as the positive direction, A and Vo are in the same direction (accelerating) a>0; On the other hand, a < 0}?
8. Experimental inference δ S = AT2? {Δ s is the displacement difference (t) in consecutive adjacent equal time}?
9. Mainly
And unit: initial velocity (VO): m/s; Acceleration (a): m/s2; Terminal speed (vt): m/s; Time (t) seconds (s); Displacement (s): m; Distance: meters; speed
: 1 m/s = 3.6 km/h?
Attention:?
( 1)
Is a vector; ?
(2) When the speed of the object is high, the acceleration is not necessarily high; ?
(3)a=(Vt-Vo)/t is only a measure, not a judgment; ?
(4) Other relevant contents:
, displacement and distance, reference frame, time and moment [see Volume I, P 19]/S-T diagram, V-T diagram/speed and rate,
[See Volume I of P24]. ?
2)
1. initial velocity VO = 0? 2. Final speed vt = gt?
3. Falling height h = GT2/2 (calculated from Vo position downwards)? 4. Inference Vt2=2gh?
Attention:?
( 1)
The initial velocity is zero.
, follow
; ?
(2)a=g=9.8m/s2≈ 10m/s2(
It is smaller near the equator, smaller than the flat land at the high mountain, and the direction is vertical downward). ?
(3)
1. displacement s = VOT-GT2/2? 2. terminal speed vt = VO-gt? (g=9.8m/s2≈ 10m/s2)？
3. Useful inference VT2-VO2 =-2gs? 4. Maximum rising height hm = VO2/2g (from the throwing point)?
5. Round trip time t = 2vo/g? (Time from throwing it back to its original position)?
Attention:?
(1) whole process: it is a straight line motion with uniform deceleration, with positive upward direction and negative acceleration; ?
(2) Sectional machining: the upward movement is a straight line movement with uniform deceleration, and the downward movement is a straight line movement with uniform deceleration.
, and
; ?
(3) The rising and falling processes have the following characteristics.
, as the speed of a point is equivalent, etc. ?
Second,
(2)-the movement
Gravity?
1)
1. horizontal speed: VX = VO? 2. vertical speed: vy = gt?
3. Horizontal displacement: x = VOT? 4. Vertical displacement: y = GT2/2?
5. Exercise time t = (2 y/g) 1/2 (usually expressed as (2h/g) 1/2)?
6. Closing speed vt = (vx2+vy2)1/2 = [VO2+(gt) 2]1/2?
The angle between the closing speed direction and the horizontal plane is β: tgβ = vy/VX = gt/v0?
7. Joint displacement: s = (x2+y2) 1/2,?
Angle α between displacement direction and horizontal plane: tgα = y/x = gt/2vo?
8. Horizontal acceleration: ax = 0；; Vertical acceleration: ay = g?
Attention:?
( 1)
be
The acceleration is g, which can usually be regarded as the synthesis of uniform linear motion in horizontal direction and free falling motion in vertical direction; ?
(2) The movement time is determined by the falling height h(y) and has nothing to do with the horizontal throwing speed; ?
(3) The relationship between θ and β is TGβ= 2tgα；; ; ?
(4) in
Time t is the key to solve the problem; 5) do
An object must have an acceleration. When the direction of velocity and the direction of resultant force (acceleration) are not in a straight line, the object is in a straight line.
. ?
2)
1.
V=s/t=2πr/T？ 2.
ω=φ/T = 2π/T = 2πf？
3.
a=V2/r=ω2r=(2π/T)2r？ 4.
f center = mv2/r = mω2r = Mr(2π/t)2 = mωv = f？
5. Period and frequency: t = 1/f? 6.
and
Relationship: v = ω r?
7.
Relationship with rotational speed ω = 2 π n (frequency and rotational speed have the same meaning here)?
8. Mainly
And unit: arc length (s): meter (m); Angle (φ): radian (rad); Frequency (f): Hertz; Period (t): seconds (s); Rotational speed (n): rpm; Radius? : meter (m);
(v) Male/female; Angular velocity (ω): radians per second;
M/sec 2.
Attention:?
( 1)
It can be provided by a specific force, resultant force or component force, and the direction is always perpendicular to the speed direction and points to the center of the circle; ?
(2) do
An object
Equal to the resultant force, the centripetal force only changes the direction of the speed, not the size of the speed, so the kinetic energy of the object remains unchanged, and the centripetal force does not do work, but the momentum is constantly changing. ?
3) gravity?
1.
: t2/r3 = k (= 4π 2/gm) {r: orbital radius, t: period, k:
(It has nothing to do with the mass of the planet, but depends on the mass of the central celestial body)}?
2.
:F=Gm 1m2/r2？ (G = 6.67× 10- 1 1N？ M2/kg2, the direction is on their connection)?
3. The sum of celestial gravity
:GMm/R2 = mg； G = general /R2? {r: celestial radius (m), m: celestial mass (kg)}?
4. Orbital velocity, angular velocity and period of the satellite: v = (GM/R)1/2; ω=(GM/R3) 1/2； T = 2π (R3/GM) 1/2 {m: mass of central celestial body}?
5. First (second, third)
V 1 = (G and r)1/2 = (GM/r)1/2 = 7.9 km/s; V2 = 1 1.2km/s； V3= 16.7km/s？
6.
Gmm/(r+h) 2 = m4π 2 (r+h)/T2 {h ≈ 36000 km, h: height from the earth's surface, r: radius of the earth}?
Attention:?
( 1)
The required centripetal force is provided by gravity, and the direction F = F million; ?
(2) Application
The mass density of celestial bodies can be estimated; ?
(3)
It can only run over the equator, and the running period and
Homocycle; ?
(4) When the orbit radius of the satellite decreases, the potential energy decreases, the kinetic energy increases, the speed increases and the period decreases. ?
(5)
What are the maximum circling speed and minimum launching speed of 7.9 km/s?
Third, force (ordinary force,
)?
1) Ordinary force?
1. Gravity g = mg? (the direction is vertical downward, g = 9.8m/S2 ≈ 10m/S2, and the point of action is at the center of gravity, which is suitable for near the surface)?
2.
F=kx？ {along the direction of recovery deformation, k:
(N/m), x: deformation (m)}?
3.
F=μFN？ {with objects
In the opposite direction, μ: friction coefficient, FN:
(N)}？
4.
0≤f, static ≤fm? (with objects
The trend is in the opposite direction, fm is
)?
5. Gravity f = gm 1m2/r2? (G = 6.67× 10- 1 1N？ M2/kg2, the direction is on their connection)?
6. Electrostatic force f = kq 1q2/r2? (k=9.0× 109N？ M2/C2, the direction is on their connecting line)?
7.
F = emotional intelligence? (E:
N/C, q: electric quantity c,
suffer
and
In the same direction)?
8.
F=BILsinθ？ (θ is the included angle between B and L, when L⊥B: F = BIL, when B//L: F = 0)?
9. Lorentz force f = qvbsin θ? (θ is the angle between b and v, when V⊥B: f = qvb, when V//B: f = 0)?
Attention:?
( 1)
K is determined by the spring itself; ?
(2) The friction coefficient μ has nothing to do with pressure and contact area, but is determined by the material characteristics and surface conditions of the contact surface. ?
(3)fm is slightly larger than μFN, which is generally considered as FM ≈ μ fn; ?
(4) Other relevant contents:
(size, direction) [see P8]; In the first volume]; ?
(5)
Symbol and unit B: magnetic induction intensity (T), L: effective length (M), I: current intensity (A), V: charged particle velocity (m/s), Q: charged particle (charged body) electric quantity (C); ?
(6)
And Lorentz force.
Judge. ?
2)
1. The resultant force on the same line is in the same direction: f = f 1+F2,? Conversely: f = f 1-F2? (f 1 & gt； F2)？
2. Synthesis of mutually angled forces:?
f =(f 12+F22+2f 1 F2 cosα) 1/2(
)? When f1⊥ F2: f = (f12+f22)1/2?
3. resultant force range: | f1-F2 |≤ f≤| f1+F2 |?
4. orthogonal decomposition of force: FX = FCOS β, FY = FSIN β (β is the included angle between the resultant force and the x axis TG β = FY/FX)?
Attention:?
The composition and decomposition of (1) force (vector) are as follows
; ?
(2) The relationship between resultant force and components is equivalent substitution, and resultant force can be used to replace the * * * interaction of components, and vice versa; ?
(3) Unless
In addition, it can also be used for graphic solution. At this time, we must choose the scale and draw strictly. ?
(4) When the values of F 1 and F2 are constant, the greater the included angle (α angle) of F 1 and F2, the smaller the resultant force; ?
(5) The combination of forces on the same straight line can be used by taking the positive direction along the straight line.
Represents the direction of force and is simplified to algebraic operation. ?
Fourth, dynamics (motion and force)?
1.
(Law of Inertia): Objects have inertia and keep it all the time.
State or static state until an external force forces it to change this state?
2.
: f = ma or a = f /ma{ by
Decide, use
Same direction}?
3.
:F=-F？ {The minus sign indicates the opposite direction, f, f? One acts on the other,
And acting force
Difference, practical application: recoil movement}?
4.
Equilibrium f = 0, generalization? {
, the principle of the three forces meeting}?
5. Overweight: FN>g, weightlessness: fn
6.
Applicable conditions: it is suitable for solving the problem of low-speed motion, but not for dealing with high-speed problems for macroscopic objects and microscopic particles [see Volume I P67]?
note:
It means that an object is at rest or moving in a straight line at a uniform speed or rotating at a uniform speed. ?
Verb (abbreviation for verb) vibrates and fluctuates (
and
) spread?
1.
F=-kx？ {F: restoring force, k: proportional coefficient, x: displacement, and the negative sign means that the direction of f is always opposite to x}?
2.
Period t = 2π (l/g) 1/2? {l: pendulum length (m), g: local.
Value under set conditions: swing angle θ
be forced
Features: f = f driving force?
4. Conditions for occurrence of * * * vibration: F driving force = F solid, A = Max * * * Prevention and application of vibration [see Volume I, P 175]?
5.
、
、
[See P2 Volume II]?
6. Wave velocity v = s/t =λf =λ/t {In the process of wave propagation, one period propagates forward by one wavelength; The wave velocity is determined by the medium itself.
7. Sound wave velocity (in air) 0℃; 332 m/s; 20℃； 344 m/s; 30℃； 349 m/s; (Sound waves are
)?
8. The waves are obvious.
Condition: Is the size of the obstacle or hole smaller than the wavelength, or is there little difference?
9.
Condition: Two waves have the same frequency (constant difference,
Similar, same vibration direction)?
10.
: by
The mutual motion between the source and the observer leads to the wave source.
Is the rate different from the receiving frequency (if they are close, the receiving frequency will increase, otherwise it will decrease [see Volume II P2 1]}?
Attention:?
(1) object
and
The frequency of driving force is independent, but depends on the vibration system itself; ?
(2) The strengthened area is the place where the peaks meet or the valleys meet, and the weakened area is the place where the peaks meet; ?
(3) The wave only propagates vibration, and the medium itself does not migrate with the wave, which is a way to transfer energy; ?
(4) Interference and
Porter has; ?
(5) Vibration image and fluctuation image; ?
(6) Other related contents: ultrasonic wave and its application [see Volume II P22]/ Energy transformation in vibration [see Volume I p 173]. ?
Six,
Change of force and momentum of an object?
1. Momentum: p = mv? {p: momentum (kg/s), m: mass (kg), v: speed (m/s), and the direction is the same as the speed direction}?
3. Impulse: I = ft? {I: Impulse (n? s)，F:
(n), t: the action time of the force (s), and the direction is f?
4.
: I = Δ p or ft = MVT-MVO? {δ P: momentum change δ P = MVT–MVO, which is vector type}?
5.
: before the total p = after the total p or p = p=p'? Can it also be m1v1+m2v2 = m1v1? +m2v2
6.
:δp = 0； Ek = 0？ {that is, the conservation of momentum and kinetic energy of the system}?
7. Number
δp = 0； 0 & ltEK & ltEKm？ {δEK: kinetic energy loss, EKm: maximum kinetic energy loss}?
8. Not at all
δp = 0； δEK =δEKm？ {Touch and connect into a whole}?
9. The object m 1 collides elastically with the stationary object m2 at the initial velocity of v 1.
v 1？ =(m 1-m2)v 1/(m 1+m2)？ v2？ = 2m 1v 1/(m 1+m2)？
10. Equal mass elastic collision 9- exchange velocity (kinetic energy conservation, momentum conservation) inference?
1 1.M horizontal velocity vo of the bullet.
Mechanical energy loss of long wood block m when it stops on a level and smooth ground and is embedded in it?
E loss = mvo2/2-(m+m) vt2/2 = fs relative? {vt:* * * * same speed, f: resistance, displacement of S relative to bullet relative to long block}?
Attention:?
(1) frontal collision is also called centripetal collision, and the speed direction is on the line connecting their "centers"; ?
(2) The above expressions are all except kinetic energy
In one-dimensional case, it can be transformed into forward algebraic operation; ?
(3) Conditions of momentum conservation of the system:
If it is zero or the system is not subjected to external force, the momentum of the system is conserved (collision, explosion, recoil, etc.). ); ?
(4) The collision process (a system composed of colliding objects in a very short time) is considered as momentum conservation.
Conservation of momentum in the process of decay; ?
(5) The explosion process is regarded as momentum conservation, and then
Converted into kinetic energy, kinetic energy increases; (6) Other related contents: recoil movement, development of rocket and space technology, and space navigation [see Volume I, p 128]. ?
7. Work and energy (work is a measure of energy conversion)?
1. work: w = fscos α (definition) {w: work (j), f:
(n), s: displacement (m), α: included angle between f and s}?
2. gravity does work: Wab=mghab? {m:
, g = 9.8m/S2 ≈ 10m/S2, hab: the height difference between a and b (hab = ha-HB)}?
3.
Do work: Wab=qUab? {q: electric quantity (c), UAB: between A and B.
(v) that is, UAB = φ a-φ b}?
4. Electric power: w = UIT (universal)? {u: voltage (v), I: current (a), t: power-on time (s)}?
5.P=W/t: p = w/t (definition)? {p: power [watt (W)], w: work done in time (j), t: time taken to do work (s)}?
6. cars
Power of: p = Fvp flat = Fving? {P: instantaneous power, p: average power}?
7. The car starts with constant power and constant acceleration, and the maximum running speed of the car (VMAX = P /f)?
8.
: p = ui (universal)? {u: circuit voltage (v), I: circuit current (a)}?
9.
:Q=I2Rt？ {q: electrothermal (J), I: current intensity (A), R: resistance value (Ω), T: electrifying time (S)}?
10.
I = u/r； p = UI = U2/R = I2R； Q=W=UIt=U2t/R=I2Rt？
1 1. kinetic energy: ek = mv2/2? {ek: kinetic energy (j), m: mass of object (kg), v: object.
(m/s)}？
12.
:EP=mgh？ {EP？ ：
(j), g: acceleration of gravity, h: vertical height (m) (from zero potential energy surface)}?
13.
:EA=qφA？ {ea: the charged body is at point a.
(j), q: electric quantity (c), φA:A:A point potential (V) (from zero potential plane)}?
14.
Doing positive work on an object will increase its kinetic energy.
W = mvt2/2-mvo2/2 or w = Δ ek?
{W = total work done by external force on an object, δEK: kinetic energy change δEK =(mv T2/2-MVO2/2)}?
15.
: δ e = 0 or ek 1+ep 1 = ek2+ep2 can also be mv12+mgh1= mv22/2+mgh2?
16. Gravity work sum
The change of gravitational work is equal to the gravitational potential energy of an object.
) WG = negative value of-δ EP?
Attention:?
(1) power indicates how fast work is done, and how much work is done indicates how much energy is converted; ?
(2)O0≤α& lt； 90O？ Do positive work; 90O & ltα≤ 180O does negative work; α = 90o does no work (when the direction of force is perpendicular to the direction of displacement (velocity), the force does no work); ?
(3) If gravity (elasticity, electric field force and molecular force) does positive work, the potential energy of gravity (elasticity, electricity and molecule) will decrease?
(4) Gravity work and electric field force work are independent of the path (see Equations 2 and 3); (5) Condition of conservation of mechanical energy: Except gravity (elasticity), other forces do not do work, but only convert between kinetic energy and potential energy; (6) Other abilities
: 1kWh (degree) = =3.6× 106J,1ev =1.60×10-19j; *(7) Spring
E = kx2/2, and
It is related to shape variables. ?
Eight,
、
1.Avon gadro constant na = 6.02×1023/mol; Molecular diameter
10-10m?
2. Measuring molecular diameter by oil film method D = V/s? {v: single molecule oil film volume (m3), s: oil film surface area (m) 2}?
3.
Content: Matter is composed of a large number of molecules; A large number of molecules do random thermal motion; Intermolecular existence
. ?
4. Intermolecular attraction and repulsion (1) r
(2) r = r0, f = f repulsion, f molecular force = 0, e.
= =Emin (minimum value)?
(3)r & gt； R0，f quote >； F repulsion, f molecular force shows gravity?
(4)r & gt； 10r0, f reference = F repulsion ≈0, f molecular force ≈0, e.
≈0?
5.
W+q = δ u {(sum of work)
These two methods of changing the internal energy of an object are actually equivalent.
W: positive work done by the outside world on the object (J), Q: heat absorbed by the object (J), δ U: increased internal energy (J), involving
Can't do it (see Volume II P40)?
6.
Kirkhner said: it is impossible to transfer heat from a low-temperature object to a high-temperature object without causing other changes (
Directionality); ?
Kelvin states that it is impossible to absorb heat from a single heat source and use it all to do work without causing other changes (directionality of transformation of mechanical energy and internal energy) {involving
Can't do it (see volume II P44)?
7.
: thermodynamics
Unable to reach {
Lower limit: -273. 15℃ (thermodynamics
)}?
Attention:?
(1) Brownian particles are not molecules. The smaller the Brownian particle,
The more obvious, the higher the temperature.
Fierce; ?
(2) Temperature is a sign of average kinetic energy of molecules; ?
3) The intermolecular attraction and repulsion exist at the same time, and decrease with the increase of intermolecular distance, but the repulsion decreases faster than the attraction; ?
(4) Molecular forces do positive work,
Decrease, at r0, F- attraction = F- repulsion, the molecular potential energy is the smallest; ?
(5) The gas expands, and the outside world does negative work on the gas W.
(6) The internal energy of an object refers to the sum of all kinetic energy of molecules and molecular potential energy of an object.
Zero, molecular potential energy is zero; ?
(7)r0 is a molecule in.
, the distance between molecules; ?
(8) Other related contents: energy transformation and invariance law [see p 4 1]/ energy development and utilization, environmental protection [see P47]/ internal energy, kinetic energy of molecules and molecular potential energy [see p 47]. ?
Nine, the nature of the gas?
1. Gas state parameters:?
Temperature: macroscopically, the degree of heat and cold of an object; Microscopically, it is a sign of the irregular motion intensity of molecules inside an object.
and
Relationship: t = T=t+273? {T:
(K)，t:
(℃)}?
Volume v: the space that gas molecules can occupy,
: 1 m3 = 103 l = 106ml？
Pressure p: single
On the product, a large number of gas molecules frequently hit the impactor wall, resulting in continuous and uniform pressure.
: 1 ATM = 1.0 13× 105 pa = 76 cmhg( 1Pa = 1N/m2)？
2. Characteristics of gas molecular movement: large intermolecular gap; Except for the moment of collision,
Weak; Molecular motion rate is high?
3.
Equation of state: p1v1/t1= p2v2/t2? {PV/t = constant, and t is
(K)}？
Attention:?
( 1)
The internal energy has nothing to do with the volume of ideal gas, but is related to the temperature and the amount of substance; ?
(2) The conditions for the establishment of Equation 3 are all ideal gases with a certain mass. When using the formula, we should pay attention to the unit of temperature, t is
(℃), and t is the thermodynamic temperature (k). ?
X. electric field
1. Two kinds of charges,
Elemental charge: (e =1.60×10-19c); charged body
Equal to an integer multiple of elementary charge?
2.
: f = kq 1q2/r2 (in vacuum) {f:
Between forces (n), k:
k=9.0× 109N？ M2/C2, Q 1, Q2: two
Electricity (c), r: two.
The distance (m) between them, the direction on their connecting line, and the sum of forces.
Like charges repel each other,
Charge attracts each other}?
3.
: e = f/q (define formula, calculate formula) {e:
(N/C), which is the vector (electric field)
), q: the number of test charges (c)?
4. The electric field formed by vacuum point (source) charge E = kq/R2? {r: distance of source charge to this position (m), q: number of source charges}?
5.
about
E=UAB/d？ {Voltage between two points (V){ UAB:AB, distance between two points in field strength direction (M)} d:AB?
6. Electric field force: f = QE? {f: electric field force (n), q: electric quantity of electric charge affected by electric field force (c), e:
(Not applicable)}?
7. Potential and
:UAB=φA-φB，UAB = WAB/q =-δEAB/q？
8. Work done by electric field force: WAB = Kwab = EQD {WAB: Work done by electric field force when charged body goes from A to B (J), Q: Charge amount (C), UAB: Between A and B in electric field.
(v) (The work done by electric field force has nothing to do with the path), e:
Intensity, d: distance between two points in the field strength direction (m)?
9.
:EA=qφA？ {ea: potential energy (J) of charged body at point A, Q: electric quantity (C), φ A: A: potential at point A (V}?
10. potential energy change δ EAB = EB-EA? {the difference of electric potential energy when a charged body moves from position A to position B in an electric field}?
1 1. Work done by the change of electric field force and electric potential energy δ eab =-wab =-quab? (potential)
Equal to the negative value of work done by electric field force)?
12. Capacitance c = q/u (definition formula, calculation formula)? {c: capacitance (f), q: electric quantity (c), u: voltage (potential difference between two plates) (v)}?
13.ping
Capacitance c = ε s/4 π KD (S: relative area of two plates, D: vertical distance between two plates, ω:
)?
ordinary
[see volume ii, p 1 1 1]?
14. acceleration of charged particles in electric field (VO = 0):w =δek Δ ek or qu = mvt2/2, vt = (2qu/m) 1/2?
15. charged particles enter at the speed Vo along the vertical electric field direction.
When deflected (regardless of gravity)?
Pingping? Vertical electric field direction:
L = vot (in-band equivalence
In a parallel charge plate: e = u/d)?
Throwing sports? Parallel electric field direction: zero initial velocity
d=at2/2，a=F/m=qE/m？
Attention:?
(1) When two identical charged metal balls are in contact, the power distribution law: primary band.
The charges are neutralized first and then divided equally, and the total amount of the same kind of original charges is divided equally; ?
(2)
from
Departure ends at
,
Do not intersect, the tangent direction is the field strength direction,
Dense field strength, the potential is lower and lower along the electric field line, perpendicular to the equipotential line; ?
(3) memorize the electric field line distribution requirements of common electric fields (see Figure [Volume II P98]); ?
(4) Electric field strength (vector) and electric potential (
) is determined by the electric field itself, and the electric field force and potential energy are also related to the electric quantity and the positive and negative charges of the charged body; ?
(5) in
The conductor is equipotential, and the surface is
The electric field line near the outer surface of the conductor is perpendicular to the surface of the conductor, the synthetic field strength inside the conductor is zero, there is no net charge inside the conductor, and the net charge is only distributed on the outer surface of the conductor; ?
(6) Capacitance unit conversion:1f =106μ f =1012pf; ?
(7) Electron Volt (eV) is the unit of energy,1EV =1.60×10-19j; ?
(8) Other relevant contents:
[See Volume II, p 10 1]/ Oscilloscope,
And its application [see volume ii, p 1 14]
[See Volume II, p 105]. ?
Eleven,
1. current intensity: i = q/t {i: current intensity (a), q: the amount of electricity passing through the lateral load surface of the conductor in time t (c), t: time (s)}?
2.
:I=U/R？ {i: conductor current intensity (a), u: voltage across the conductor (v), r: conductor resistance (ω)}?
3. Resistance and resistance law: r = ρ l/s {ρ:
(Ω? M), l: conductor length (m), s: conductor.
Product (m2)?
4.
: I = E/(R+R) or E = IR+IR can also be E = U inside +U outside?
{i: total current in the circuit (a), e: power supply.
(v), r: external circuit resistance (ω), r: internal resistance of power supply (ω)}?
5. Electricity and
: w = uit, p = ui {w: electric work (j), u: voltage (v), I: current (a), t: time (s), p:
(W)}？
6.
: q = i2rt {q: electrothermal (j), I: current through the conductor (a), r: resistance value of the conductor (Ω), t: on-time (s)}?
7.
Chinese: Since I = u/r, W = q, W = q = UIT = I2RT = U2T/r?
8. Total power activity, power supply
, power efficiency: pTotal = IE, pOutput = IU, η = ptout/ptotal {i: total circuit current (a), e: power supply.
(v), u: terminal voltage (v), η: power efficiency?
9. Series/parallel circuit? Series circuit (p, u, r are proportional)? Parallel circuit (P, I, R are inversely proportional)?
Resistance relationship (series-same and anti-parallel)? R string = r 1+R2+R3+? 1/R and = 1/R 1+ 1/R2+ 1/R3+？
The relationship now? I always = i 1 = I2 = i3? IUnion = I 1+I2+i3+？
Voltage relationship? U total = U 1+U2+U3+？ U total = U 1 = U2 = U3？
Power distribution? P total = P 1+P2+P3+? P total = P 1+P2+P3+