All power calculation formulas Note: not electrical power

All power calculation formulas Note: not electrical power

power
Power calculation formula of force: because w = f (f force) * s (s displacement) (definition formula of work), the formula of power calculation can also be deduced as P = f · V (when v represents average speed, the power calculated is the average power of corresponding process, and when v represents instantaneous speed, the power calculated is the instantaneous power of corresponding state)
Power calculation formula: P = w / T (average power) P = Fv (instantaneous power)
What is the calculation formula of voltage current resistance?
Ohm's law voltage equals current times resistance
The molar mass of copper is m and the density is ρ. There are n free electrons per mole of copper atom. Now there is a copper wire with a cross-sectional area of S. when the current passing through is I, the average rate of directional movement of electrons is ()
A. Speed of light CB. Inesmc. ρ inesmd. Mines ρ
Let v be the rate of directional movement of free electrons in a copper wire, and t be the time taken for free electrons to move from one end to the other. Then the length of the wire is L = VT, the volume is v = SL = SVT, and the mass is m = ρ VTS. The number of free electrons in this wire is n = mmna = ρ vtsmna. These electrons can pass through in t time
What is the area formula of a circle
The square of π R
When the resistance of the external circuit is 8 Ω and 2 Ω respectively, the heat generated in the external circuit is exactly equal in unit time, then the internal resistance of the power supply is ()
A. 1ΩB. 2ΩC. 4ΩD. 6Ω
When the resistance of external circuit is divided into 8 Ω, according to Ohm's law of closed circuit: I1 = ER1 + r = E8 + R ① When the resistance of external circuit is divided into 2 Ω, according to Ohm's law of closed circuit, I 2 = Er 2 + r = E 2 + R ② According to the unit time in the external circuit heat is exactly equal: i12r1 = i22r2 ③ From the solution of (1) to (2), r = 4 Ω, so C is chosen
Xiaoming's electric energy meter is marked with "220V & nbsp; & nbsp; 10A". The total power of household appliances is 1300W. When all appliances are working, can we install a 1100W air conditioner to use at the same time? Please give me your reasons
The total power of the air conditioner and the original household appliances is 1300W + 1100W = 2400W, and the maximum value of the energy meter is p = UI = 220V × 10A = 2200W; Therefore, the total power of the air conditioner exceeds the maximum value that can be borne by the electric energy meter, which will lead to inaccurate counting or burn out of the electric energy meter and cause a fire in the circuit. So answer: the air conditioner can not be used with all electrical appliances at home at the same time. Because the total power of the air conditioner when used with all electrical appliances is 2400W, which exceeds the maximum value of 2200W that the electric energy meter can bear, it will lead to a fire The electric energy meter can't count accurately or even burn out, which leads to circuit fire
It is known that the atomic weight of aluminum is 27, the density of aluminum is 2.7 * 10 cubic kg / M cubic, then what is the molar volume of aluminum? What are the aluminum atoms in 1g aluminum?
The molar volume of aluminum is 27 [g / mol] / 2.700 [g / cm3] = 10 cm3 / mol
The result of the second one comes out directly: Na / 27
The atomic weight of aluminum is 27, so the molar volume of aluminum is 10 cubic centimeter when the mass of 1 mol aluminum is 27 g divided by the density
The number of aluminum atoms = 1g / 27g mol * Avogadro constant = 22nd power of 2.23 * 10
Circular volume formula
For a round one-third of the area urgent!
Circle area formula = square of radius
The volume formula of a sphere = (4 / 3) π R ＾ 3
The formula of sphere surface area: s (sphere) = 4 π R ^ 2. The formula of sphere volume: v = (4 / 3) π R ^ 3.
Three quarters of the cube of radius x
Circle area formula = square of radius
Circle area formula = square of radius
The volume formula of a sphere = (4 / 3) π R ＾ 3
Area: the square of π R
As shown in the figure, in the circuit, the internal resistance R of the power supply is 6 ohm, the total power of the power supply is 400W, the power consumed by the external circuit is 376w, and the resistance R1 = 5.. 1. The current in the circuit 2. The electromotive force E of the power supply 3. The power consumed on the resistance R2
The picture is not easy to pass. It's probably a rectangle. Below is the power supply [there are four vertical lines]. E and R are also in the power supply. Above are two resistors, R1 and R2 from left to right
Ie = p outside + P inside
400=376+I^2*6
I=2A
IE=400
E=400/2=200V
P outer = I ^ 2R outer
376 = 4 * r outer
R outer = 94 Ω > R1
So tandem
P1=I^2R1
=4*5=20W
P outside = P1 + P2
376=20+P2
P2=356W
The rated voltage of an electric heater is 220 v. when it works in household appliances for 12 hours, the reading of electric energy meter changes from 4763.2 to 4778.2
How much work does the electric heater do in 12 hours? How much heat does the electric heater release in 10 minutes?
4778.2-4763.2 is the work done by electrical appliances, 15kwh. Dividing this work by 12 is its actual power of 1.25kw. Because it is a family circuit, the rated voltage is 220V, which is the rated power. The working time can be calculated by T = w / P, and the latter is easy to do