What are all the formulas in physics, especially in mechanics and electricity

What are all the formulas in physics, especially in mechanics and electricity

Supplementary formula
Speed: v = s / T
Density: ρ = m / V
Gravity: g = mg
Pressure: P = f / S
Buoyancy: F floating = g row = ρ liquid GV row
Floating: F = g
Lever balance condition: F1 × L1 = F2 × L2
Work: w = FS
Power: P = w / T = FV
Mechanical efficiency: η = w useful / W total = GH / Fs = g / FN (n is the number of strands of pulley block)
Heat: q = cm △ t
Calorific value: q = MQ
Ohm's Law: I = u / R
Joule's Law: q = I & sup2; RT = u & sup2 / RT = uit = Pt (the last three formulas are applicable to pure resistance circuit)
Electric work: w = uit = Pt = I & sup2; RT = u & sup2 / RT (the latter two formulas are applicable to pure resistance circuit)
Electric power: P = UI = w / T = I & sup2; r = u & sup2 / R
Dynamics:
Gravity g (n) g = Mg (M: mass; G: 9.8n/kg or 10N / kg)
Density: ρ (kg / m3) ρ = m / V (M: mass; V: Volume)
Resultant force: F (n) direction is the same: F = F1 + F2; direction is opposite: F = F1-F2 direction is opposite, F1 > F2
Buoyancy: F floating (n) f floating = g object - G view (g view: gravity of object in liquid)
Buoyancy: F floating (n) f floating = g object (this formula only applies to floating or suspending objects)
Buoyancy: F floating (n) f floating = g row = m row, g = ρ liquid GV row (g row: the gravity of the discharged liquid; m row: the mass of the discharged liquid; ρ liquid: the density of the liquid; V row: the volume of the discharged liquid (i.e. the volume immersed in the liquid))
Balance condition of lever: f1l1 = f2l2 (F1: power; L1: power arm; F2: resistance; L2: resistance arm)
Fixed pulley: F = g object, s = H (F: the tension on the free end of the rope; G object: the gravity of the object; s: the distance that the free end of the rope moves; H: the distance that the object rises)
Moving pulley: F = (g object + G wheel) / 2 s = 2 h (g object: gravity of object; G wheel: gravity of moving pulley)
Pulley block: F = (g object + G wheel) s = n h (n: number of segments of rope passing through movable pulley)
Mechanical work: w (J) w = fs (F: force; s: distance moved in the direction of force)
Active work: wyou = g object H
Total work: wtotal wtotal = FS when the pulley block is placed vertically
Mechanical efficiency: η = Wye / wtotal × 100%
Power: P (W) P = w / T (W: work; t: time)
Pressure P (PA) P = f / S (F: pressure; s: stressed area)
Liquid pressure: P (PA) P = ρ GH (ρ: density of liquid; H: depth [vertical distance from liquid surface to desired point])
Heat: Q (J) q = cm △ t (C: specific heat capacity of material; m: mass; △ T: temperature change value)
Heat released by fuel combustion: Q (J) q = MQ (M: mass; Q: calorific value)
electrical science;
Series circuit current I (a) I = I1 = I2 = The current is equal everywhere
Series circuit voltage U (V) u = U1 + U2 + The series circuit acts as a voltage divider
Series circuit resistance R (Ω) r = R1 + R2 +
Parallel circuit current I (a) I = I1 + I2 + The main current is equal to the sum of the branch currents (shunt)
Parallel circuit voltage U (V) u = U1 = U2 =
Parallel circuit resistance R (Ω) 1 / r = 1 / R1 + 1 / r2 +
Ohm's Law: I = u / R
The current in the circuit is proportional to the voltage and inversely proportional to the resistance
Current definition formula I = q / T (Q: charge quantity (Coulomb); t: time (s))
Electric work: w (J) w = uit = Pt (U: voltage; I: current; t: time; P: electric power)
Electric power: P = UI = I2R = U2 / R (U: voltage; I: current; R: resistance)
The relationship between electromagnetic wave velocity and wavelength and frequency: C = λ ν (C: wave velocity (the wave velocity of electromagnetic wave is constant, equal to 3 × 108m / s); λ: wavelength; ν: frequency)

The third grade physics electricity formula question
Heat formula: q = i2rt, which is a general formula of heat, suitable for pure resistance circuit and non pure resistance circuit
There is another formula: q = uit and q = u 2 / R · T, which are only applicable to pure resistance circuits
I want to know why "q = i2rt" can be used in any circuit, while "q = uit and q = U2 / R · T" can only be used in pure resistance circuit
But according to Ohm's law, the above can be transformed into each other. Why?

Ohm's Law (U = IR) in junior high school is in a narrow sense, which only applies to pure resistance circuit. Therefore, in pure resistance circuit, q = i2rt and q = uitq = U2 / R · t can be transformed into each other. Generalized Ohm's law is e = I (R + R) e is the electromotive force of power supply, R is the internal resistance of power supply. In non pure resistance circuit, electric energy is not only converted into Joule heat, but also

Simplification, evaluation: M2-1 / m2-2m + 1 △ (m-1-m + 1 / m-1), where M = √ 3

(m²-1)/(m²-2m+1)÷[m-1-(m+1)/(m-1)]
=(m+1)(m-1)/(m-1)²÷[m-1-(m+1)/(m-1)]
=(m+1)/(m-1)÷[(m-1)²-(m+1)]/(m-1)
=(m+1)/[(m-1)²-(m+1)]
=(m+1)/m(m-3)
m=√3
So the original formula = (√ 3 + 1) / 3 (√ 3-3) = - (2 + √ 3) / 3

Acceleration Formula s = 1 / 2A * (T square), right?

(1)
When the initial velocity is 0, that is, V0 = 0,
The formula of uniform acceleration is s = 1 / 2 * a * T ^ 2
(2)
When the initial velocity is not 0, that is, V0 is not equal to 0,
The formula of uniform acceleration is s = v0t + 1 / 2 * a * T ^ 2
(3) If it is not a uniform acceleration motion, the formula does not hold

The solution equation (1) 2 / 1 x-3 / 1 x = 18 (2) 8 x-7.5 x = 40% × 20%

1、 x=108
2、 x=0.16

The tan (x) curve of 0 ~ 360 degrees can be displayed with "*"

If so, the XY axis can be reversed,
Loop from 0 to 360 / 2pi
【
Call Tan function
Multiply the result by 20
Loop from 0 to result
Output space
Output asterisk
】
However, it seems that there is a problem with PI / 2. The domain of definition should be well limited

(x + 2) ^ 2 = 8x requires cross multiplication

x²+4x+4=8x
x²-4x+4=0
(x-2)(x-2)=0
x=2

Translate the point a (2,3) down four unit lengths, and then to the right two unit lengths to get the coordinates of point a '

A '(4, - 1) that's right. I'll learn it!

Given that the maximum value of quadratic function y = f (x) is equal to 13, and f (3) = f (- 1) = 5, then the analytic expression of F (x) is f (x)=______ ．

∵ the maximum value of quadratic function y = f (x) is equal to 13, and f (3) = f (- 1) = 5, the symmetry axis of the function is: x = 1, that is, f (x) = a (x-1) 2 + 13 ∵ f (3) = 4A + 13 = 5 ∵ a = - 2, then f (x) = - 2 (x-1) 2 + 13 = - 2x2 + 4x + 11, so the answer is: - 2x2 + 4x + 11

A function proof problem
It is proved that if f '(x) = C and C is a constant, then f (x) must be a linear function
How to write the key format~

Integral, because f '(x) = C, C is a constant, so f (x) = CX + C1, C is a constant, C1 is a real number, so linear