Circuit diagram of series circuit and parallel circuit, current, voltage, resistance, distribution of voltage and current, electric power and electric power,

Circuit diagram of series circuit and parallel circuit, current, voltage, resistance, distribution of voltage and current, electric power and electric power,

Serial number physical quantity calculation formula remarks
The speed of sound is 340m / s and the speed of light is 3 × 108 M / s
2. Temperature: 0C
3 / X09 density / X09 ρ = m / V / x091 g / C m3 = 103 kg / m3
4  x09f = F1 - F2
F = F1 + F2, f9f1 and F2 are on the same straight line and in opposite directions
F1 and F2 are on the same straight line and in the same direction
It is suitable for solid, liquid and gas
P = ρ g h is suitable for cylinders in solids
P = ρ GH, the liquid pressure can be calculated directly
\Standard atmospheric pressure = 76 CMHG column = 1.01 × 105 PA = 10.3 m water column
6. Buoyancy: F floating = f up - f down
② F = g – f
③ Floating: F = g
④ F floating = g row = ρ liquid g V row
⑤ Determine the buoyancy according to the floating and sinking conditions
(1) Determine whether the object is buoyant
(2) Judging the state of an object according to its floating and sinking conditions
(3) Find out the appropriate formula to calculate buoyancy
\Conditions of floating and sinking (premise: the object is immersed in liquid and only subject to buoyancy and gravity)
① F floating ＞ g (ρ liquid ＞ ρ substance) floating up to floating; ② f floating = g (ρ liquid = ρ substance) suspension
③ F floating < g (ρ liquid < ρ substance) sinking
Lever balance condition is also called lever principle
8  X09 pulley block  x09f = g / n
F = (g motion + G object) / n
S = NH (V f = n V g) - X09 ideal pulley block
Ignore the friction between the axles
n: Number of strands of rope acting on moving pulley
9 / X09 slope formula / x09f L = GH / X09 for smooth slope
10 / x09w = f s = P T / x091j = 1n &; m = 1W &; s
11 / x09p = w / T = f ν / x091kw = 103 W, 1MW = 103 kw
12. Active work: useful = GH (vertical lifting) = fs (horizontal movement) = wtotal - wtotal = η wtotal
Additional work = wtotal – Wye = gdynamic H (ignoring friction between axles) = f l (inclined plane)
Total work = w useful + W amount = f s = w useful / η
Mechanical efficiency: η = w useful / wtotal = g / (n, f)
=G matter / (g matter + G action) X09 definition
It is suitable for movable pulley and pulley block
16  x09q = cm △ t q = QM  X09
Ohm's law is applicable to pure resistance circuit
Joule's law is applicable to all electric circuits
nineteen
\X09 electric power
\X09 definition formula - w = uit = Pt (Universal)
Derived formula - w = i2rt; (string)
W = (U2 / R) t; (and) X09 (1) when using the formula, the physical quantities are usually in SI units
(2) The definition of physical quantity also needs its physical meaning
(3) Pay attention to the scope of the formula
(4) Flexible deformation of the basic formula
Definition of electric power: P = w / T = UI (Universal)
Derived formula: P = I2R; (string) P = U2 / R; (Union) X09
21 / x09i = I1 = I2 u = U1 + U2 r = R1 + R2 / X09
22 / x09i = I1 + I2 u = U1 = U2
1/R=1/R1+1/R2 \x09
R=R1R2 /(R1+R2)