1. The rational numbers x and y are suitable for the following relations: x + | x | + y = 10, | y | + X-Y = 12 2. Let a < B < C < D, find the minimum value of | x-a | + | X-B | + | x-C | + | X-D | 3. Let a, B, C, D and E be integers, and | A-B | = 19, | B-C | = 7, | C-D | = 5, | D-E | = 4, | e-A | = 11, and a + B + C + D + e = 56 4. If A-1 = B + 2 = C-3 = D + 4, try to judge the size relationship of a, B, C, D 5. The absolute value of the number a is twice that of the number B. on the number axis, the numbers a and B are on the same side of the origin, and the distance between the two corresponding points is equal to 10. Calculate the two numbers Note:

1. The rational numbers x and y are suitable for the following relations: x + | x | + y = 10, | y | + X-Y = 12 2. Let a < B < C < D, find the minimum value of | x-a | + | X-B | + | x-C | + | X-D | 3. Let a, B, C, D and E be integers, and | A-B | = 19, | B-C | = 7, | C-D | = 5, | D-E | = 4, | e-A | = 11, and a + B + C + D + e = 56 4. If A-1 = B + 2 = C-3 = D + 4, try to judge the size relationship of a, B, C, D 5. The absolute value of the number a is twice that of the number B. on the number axis, the numbers a and B are on the same side of the origin, and the distance between the two corresponding points is equal to 10. Calculate the two numbers Note:

4 C greater than a greater than b greater than D
Taking A-1 as the standard, a minus one C needs to minus three C ＞ a
If a minus a B, add two a greater than B
Take B as the standard, B plus 2, D plus 4
b+2=d+4
b+d+2
b＞d
So c > a > b > D

A water company in a city charges water fees according to the following standards: if each household uses less than 10m3 of water per month, it will charge 1.5 yuan per cubic meter; if each household uses more than 10m3 of water per month, it will charge 2 yuan per cubic meter for the excess. Xiaoliang's monthly water fee is not less than 25 yuan, so how much is his household's water consumption (xm3) this month at least? Please list the inequalities for X

Let Xiaoliang's monthly water consumption be xm3. According to the meaning of the question, 1.5 × 10 + 2 (X-10) ≥ 25

How many tons is two tons six grams

Equal to 2.000006 tons, 1 ton equal to 1000000 grams

If 2A + 3B equals 1, then 3-4a-6b equals?

2a＋3b=1
Then:
3－4a－6b
=3－2(2a＋3b)
=3－2×1
=3－2
=1

Who can give me some questions about electric power

Exercises of electric power for junior high school students
[2005-11-06 10:55:19]
1. In the home circuit, the physical quantity usually measured by the electric energy meter is ()
A. Electric power B. electric work C. voltage D. current (intensity)
2. A and B lamps with the same rated voltage are connected in series on the circuit, and a lamp is brighter than B lamp
Right ()
A. The rated power and actual power of lamp a are higher than that of lamp B. the rated power and actual power of lamp B are higher than that of lamp a
C. The rated power of a lamp is small, the actual power is large D. the rated power of B lamp is small, the actual power is large
3. The resistance of a certain electric heater is 220 ohm, and the current passing through it is 2 A. within 10 seconds, the resistance is 220 ohm
What is the heat released by the electric heater______
4. An electric lamp marked with "220v100w" works normally for 40 hours, and the consumed electric energy is
______ Kilowatt hour
5. Connect the "6v3w" and "6v1w" lamps in series into a certain circuit
The voltage at both ends of the circuit should be_____ V. (filament resistance does not vary with temperature)
6. Connect a small bulb with a rated voltage of 4.8V and a constant resistance R in parallel in a certain circuit, and the lamp will turn off
The current in the main circuit is 1.2 A. if they are connected in series in another circuit, it is small
The actual power of the bulb is 1 / 4 of its rated power, and the power consumed by the constant resistance R is 0.24
W. what is the rating of the small bulb________ Watt. (assuming filament resistance does not change with temperature)
7.1 kwh is equal to 3.6 × 106 joules, and the annual power generation capacity of the Three Gorges small power station will be built soon
Up to 8.47 × 1010 kwh, equivalent to___________ coke
8. The normal working current of an oven is 5 A, the electric power is 1 kW, and the resistance of the oven is 0____
Oh, half an hour______ degree
9. There are two resistance wires. The ratio of their resistance is 2:1. Connect them in parallel and the voltage is
In the circuit of u, the ratio of heat released by them in the same time is ()
A.1:2 B.2:1 C.1:4 D.4:1
10. Xiaoming connects the A and B lamps with the rated voltage of 220 V in series with the power supply of 220 V and closes them
After the switch, a lamp lights up, B lamp does not light up, then: A and B two lamp in the current ratio is____ ; a
Lamp resistor____ Resistance of lamp B and voltage of lamp a_____ Voltage at both ends of lamp B (fill in "greater than
”Less than or equal to)
11. The panel of household electric energy meter (kilowatt hour meter) is marked with "3000 rpm / kWh", which can be accessed
When a "220v300w" electric appliance works normally, the turntable of the electric energy meter turns ()
A. 0 to B.5 to c.15 to d.30
12. If the two fixed value resistors r1r2 are connected with the power supply in some form, the consumption of R1 will be less
The electric power is 9 watts; if the two resistors are connected to the power supply after being replaced by another connection, R1 will be cancelled
The power consumption is 16 watts and the current through R2 is 4 A. then the power supply voltage and the resistance of r1r2
How big is each? (the supply voltage remains unchanged)
13. It is known that the resistance relationship between the two lamps L1 and L2 is r1p2
C. According to P = I2R, P1

Vector projection problem
Suppose vector a, vector B. then the projection of a on B is?: a * (B / | B |)
Or a * cos {a, B}?
It's better to be more detailed. Why!

There's something wrong with what you've written. Let me rewrite it: first of all, it's clear that "the projection of a on B" is still a vector. Its direction is the direction of B, and its size is: make a vertical line of vector B through the endpoint of a, and the length of that shadow is called "projection". First, divide B by | B | to get the unit vector B / | B | in the same direction as B

Working for several years, please tell us the power (W) and what by what?

The symbol of mechanical power is p, the unit is Watt, and the symbol is w
The formula is: P = w / T
The sign of electric power is also p, the unit is Watt, and the sign is w
The formula is: P = w / T = UI = I ＾ 2R = u ＾ 2 / R

After a free falling ball falls for a period of time, it contacts with the spring. From the time it contacts the spring to the time when the spring compresses to the maximum extent, what is correct in the following descriptions of the motion state of the ball
A. After contact, the ball decelerates, the absolute value of acceleration becomes larger and larger, the speed becomes smaller and smaller, and finally equal to zero
B. After contact, the ball first accelerates and then decelerates, and its speed first increases and then decreases to zero
C. After contact, the place where the velocity is zero is the place where the spring is compressed the most, and the place where the acceleration is zero is also the place where the spring is compressed the most
D. After contact, the place where the velocity of the ball reaches its maximum is the place where the acceleration equals zero

D

The frequency of alternating current in domestic circuit is 50 Hz, and the cycle is () seconds. The current direction changes () times in a cycle, and the current direction changes () times in a second

The frequency of alternating current in domestic circuits in China is 50 Hz, and the cycle is (20 millisecond). The current direction changes (twice) in one cycle, and changes (100 times) in one second

If two forces in different directions are applied to a spring scale, that is, the two forces are balanced, does the indication of the spring scale change

If the two forces are balanced, the indication index of the spring scale is the size of one force, provided that the two forces are equal