How to draw sub vector, to draw a little more detail, it is best to give a few examples

The sub vector refers to two or more vectors that can be synthesized (that is, added) to generate the final vector. To draw the sub vector, there must be specific requirements, otherwise a vector can draw many kinds of sub vectors. See figure for details. Just divided into two vectors can have many: & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; If it is divided into right angles, the length of the two components of the right angle can be calculated according to the conditions, and then the two components can be drawn

How to express negative sequence current with vector graph

10. 0 degrees. Y, 120 degrees. Z, 240 degrees

The impedance of each phase of three-phase symmetrical load is Z = (8 + J6) Ω, the rated voltage is 380V, and the on-line voltage is 380V three-phase circuit
(1) What kind of connection
(2) RMS of each phase current and RMS of line current
(3) Effective power of circuit

(1) The rated voltage of each phase load is 380V, so it is Δ connection
(2) Effective value of phase current = 380 × √ (8 ^ 2 + 6 ^ 2) = 38 (a)
Effective value of line current = √ 3 × 38 ≈ 65.8 (a)
(3) Φ = arctg (6 / 8) = 36.9 (degree)
Effective power of circuit = 380 × 38 × 3 × cos, Φ≈ 35 (kw)
Or: effective power of circuit = 380 × 65.8 × √ 3 × cos Φ≈ 35 (kw)
Answer: Yes .
Note: "effective power" is called "active power" in Electrotechnics

Why do negative numbers multiply negative numbers to get positive numbers

Because this is an axiom, just like why one plus one equals two, why two straight lines are parallel and the same angle is equal

1. After the driver steps on the brake, the car decelerates with an acceleration of 2m / S2, and its displacement in the last 2 seconds and the last 1 second before stopping is () m and () m respectively
2. A car moves in a straight line at a speed of 15m / s. when the car passes through ground a, the police find that the car is speeding. After 1.1s, the police drive the motorcycle from ground a to catch up with the car at an acceleration of 2m / S2,
(1) How long does it take for the police to catch up with the car?
(2) When and how far were they apart before they met?

The first question is 6m, 4m

If the first n terms of sequence {an} and Sn = 2n − 1, then A3=______ ．

The answer is: A3 = s3-s2 = (23-1) - (22-1) = 7-3 = 4

The speed of the car is 15m / s on the straight road, and it decelerates at an acceleration of 5m / S2 in case of emergency braking. The displacement of the car in 4S after braking is 0

The time required for the car to decelerate to 0 t = V0 / a = 15 / 5 = 3S
It will decelerate to 0 in 3S after braking, and will be stationary in the next 1s
Displacement S = (1 / 2) at ^ 2 = (1 / 2) × 5 × 3 ^ 2 = 22.5m

In the early training, Xiao Ming and Xiao Gang practiced long-distance running on the 400 meter circular track. It is known that Xiao Gang's speed is 4 meters per second, and Xiao Ming's speed is 1.5 times that of Xiao Gang. If two people start from the same starting point and run in the same direction, how many seconds will they meet for the first time? If two people start from the same starting point and run in the opposite direction, how many seconds will they meet for the first time? Kneel down and beg

Xiaogang's speed is 4 meters per second, and Xiaoming's is 1.5 times as fast as his, 4 * 1.5 = 6 meters per second. If he runs in the same direction, the first encounter is when Xiaoming runs 400 meters more than Xiaogang, and Xiaoming runs 2 meters more than Xiaogang per second, so 400 / 2 = 200 seconds, and then he meets 200 seconds later
If they run in the opposite direction, they meet when they finish a lap together. The sum of their speed is 4 + 6 = 10 meters per second, 400 / 10 = 40 seconds, and they meet after 40 seconds

2. A shop sells teapots and teacups, 20 yuan for each teapot and 5 yuan for each teacup. The shop has two kinds of preferential policies:
(1) Buy a teapot and give away a teacup;
(2) According to 92% of the total price, a customer needs to buy 4 teapots and several teacups (no less than 4)
Excuse me: when customers buy the same number of tea cups, which preferential method is used to save money?
1. If you sell a batch of goods at the beginning of the month, you can make a profit of 1000 yuan, and you can reinvest the sum of the principal and interest, and you can get 1.5% interest at the end of the month. If you sell this batch of goods at the end of the month, you can make a profit of 1200 yuan, but you have to pay 50 yuan for safekeeping
2. In order to limit the unit's water consumption, a city's water supply company only gives a unit 3000 tons of planned water consumption per month, with a charge of 0.5 yuan per ton of planned water consumption and 0.8 yuan per ton of excess water consumption. If the unit builds its own pump house to pump water, it needs to pay 500 yuan per month for management, and 0.28 yuan per ton of water, It is known that the cost of pumping a ton of water is 0.07 yuan
3. A person's mobile phone (mobile phone) can choose one of the two charging methods. The first method is to pay the monthly rent of 50 yuan, and then charge 0.40 yuan for each call. The second method is to charge 0.60 yuan for each call without paying the monthly rent?
The article is quoted from:

(1) scheme 1. Y = 4 × 20 + 5 × (x-4) y = 5x + 60 scheme 2. Y = 0.92 × (4 × 20 + 5x) y = 4.6x + 73.6. (2) when x + 60 ＞ 4.6x + 73.6, i.e. x ＞ 34, the second method saves money

The point representing an integer on the number axis is called integral point. The unit length of a certain number axis is 1cm. If a line segment AB with length of 2012cm is drawn on the number axis at will, the integral point covered by the line segment AB is______ &Nbsp; one

According to the meaning of the question: ① when the starting point of line AB is on the whole point, cover the number of 2013; ② when the starting point of line AB is not on the whole point, that is, between two whole points, cover the number of 2012, so the answer is: 2013 or 2012

How to draw sub vector, to draw a little more detail, it is best to give a few examples