Why is the calculation formula of electric power of three-phase circuit P = 1.732 * line voltage U * line current I? How is it deduced?

Why is the calculation formula of electric power of three-phase circuit P = 1.732 * line voltage U * line current I? How is it deduced?

P = 1.732 × line voltage U × phase current I = 3 × phase voltage U × phase current I
Increase the phase voltage by three times
∵ 3 × phase voltage U = 3 × 220 = 660 (V)
1.732 × line voltage U = 1.732 × 380 ≈ 660 (V)

How to calculate the electric power and power of DC circuit?

1. Electric work (1) the work done by the electric field force when the current passes through a certain circuit in a period of time is called electric work. (2) the calculation formula is w = Pt, W is electric work, (3) the unit is Joule (J). 2. Electric power (1) definition: the electric power of a consumer is equal to the electric energy it consumes in 1s, that is, electric power = work / time

It takes eight hours for a truck to go from place a to place B, and six hours for a bus to go from place B to place A. after one hour, the bus starts. How many hours after the bus starts, the two cars meet?

(1-18) / (18 + 16) = 78 / 724 = 3 (hours) a: the two cars meet three hours after the bus leaves

If 16 and (a + 3) are opposite numbers, then what is the rational number a?

The opposite of 16 is - 16, a + 3 = - 16, a = - 19

Physical momentum and energy
5. When a bullet hits a suspended sandbag horizontally and stays in it, part of the kinetic energy of the bullet is converted into internal energy. In order to increase the proportion of the amount converted into internal energy in the original mechanical energy of the bullet, the method that can be used is ()
(1) shorten the rope of hanging sand bag; (2) increase the speed of bullet
(3) reduce the mass of bullets (4) increase the mass of sandbags

Let the internal energy increase, that is, let the mechanical energy of the system change as much as possible relative to the original mechanical energy of the bullet. Specifically, let (initial kinetic energy of the bullet - Final kinetic energy of the system) / initial kinetic energy of the bullet. The larger the amount, the better
Let V 0 be the initial velocity of the bullet, then V 0 / (M + m) is the final velocity of the system, M is the mass of the bullet and M is the mass of the sandbag
Thus, the kinetic energy change is 1 / 2 (MV0 ^ 2-m ^ 2 * V0 ^ 2 / (M + m)) = 1-m / (M + m)
After a simple transformation, we can see that to increase this quantity, the smaller the M / M quantity, the better
Therefore, it is feasible to reduce the bullet mass or increase the sandbag mass
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The sum of (1) 6 times X and 24 is 90. (2) 5 times x minus 2 equals 30. (3) 7 plus 2 times x is 15

6x+24=90
6x=66
x=11
5x-2=30
5x=32
x=6.4
7+2x=15
2x=8
x=4

The speed of a car with mass m = 1 & nbsp; 000kg passing through a circular arch bridge is constant, and the radius of the arch bridge is r = 5m. G, taking 10m / S2, we can find: (1) the speed of the car when the pressure of the car on the arch bridge at the highest point is half of the weight of the car; (2) the speed of the car when the pressure of the car on the arch bridge at the highest point is zero

(1) (2) when the pressure of the vehicle to the bridge is zero, Mg = mv22r, the solution is V2 = RG = 50M / s ≈ 7.1 & nbsp; m / s

6 △ 2 / 3-3.5x equals 6 solutions

6÷2/3－3.5x＝6
9－3.5x＝6
3.5x＝9－6
3.5x＝3
x＝6/7.

A and B are 490 km apart. If they start at the same time, they will meet in 7 hours. If a starts driving for 7 hours and B starts again, two cars will meet two hours later, and the speed of two cars will be calculated

Two car speed x, y
7(x+y)=490
7x+2(x+y)=490
The results are as follows
x=50
y=20
A speed of 50 km / h, B speed of 20 km / h

1-2+3-4+5-6+… +A brief account of 2001-2002

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