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It is known that the area of right angle △ ABC is y, ab ⊥ AC, and ab = X-1, AC = x + 1. Find the analytic expression of function of Y with respect to X and the domain of definition of function
The analytic expression of Y with respect to X is y = 1 / 2 (x + 1) (x-1) or y = 1 / 2 (X & # 178; - 1);
Domain: X ≠ 1 and X ≠ - 1
If a right triangle with an angle of 60 ° has a perimeter of Y and a hypotenuse of X, then the functional relationship between Y and X is___ (better give a process)
Because the hypotenuse is x, there is an angle of 60 degrees, so the other angle is 30 degrees, so the right angle side of 30 degrees is 1 / 2x, and the right angle side of 60 degrees is 2 / 2 root sign 3x, so y = x + 1 / 2x + root sign 3 * X / 2
1. The output voltage of the generator is 230V, and the conductor with resistance of 0.0025 Ω per meter is used to deliver power to the construction site 200m away. The current in the line is 5A under normal power consumption, and the voltage on the construction site is v
If the electric appliance is used to short-circuit the current of the transmission line, the current of the second floor. 2 wires
r=0.0025×200×2＝1Ω
U line = IR = 5V
U = 230-5 = 225v
Xiaowei thought: "from Ohm's law formula I = ur, r = UI can be obtained. R = UI indicates that the resistance R of a conductor is directly proportional to the voltage u at its two ends and inversely proportional to the current I passing through the conductor." is this statement right? Why?
A: No, because the resistance has nothing to do with the voltage at both ends and the current passing through it, but only with its material, length, cross-sectional area and temperature
The output voltage of the generator is 230V. A conductor with a resistance of 0.0025 Ω per meter is used to deliver power to the construction site 200m away. When the current in the line is 5A under normal power consumption, the voltage obtained on the construction site is 5______ 5. If there is a short circuit in the electrical appliances on the construction site, the current on the transmission line is______ A. (electricity is transmitted by two wires)
According to Ohm's law, R total = UI = 230v5a = 46 Ω; according to the resistance characteristics of series circuit, R total = R total - R1 = 46 Ω - 1 Ω = 45 Ω. According to Ohm's law, the voltage on the construction site is u = IR total = 5A × 45 Ω = 225v; if there is a short circuit in the consumer, the current I '=
The resistance of a resistance wire is 9 Ω. If it is evenly elongated to 3 times of the original length, the resistance is 9 Ω_______ If it is cut into three equal length sections and twisted together, the resistance is_______ .
81 1
The resistance value is inversely proportional to the thickness of the wire, and is directly proportional to the length of the wire
The volume of the west line will remain unchanged. If we change the length of the line by three times, the resistance will be increased by three times, and then the area will be reduced by three times, and the resistance will be increased by three times, which will be nine times
In the same way
Xiaoqiang bought a coil of 100 m long and 2 mm diameter copper wire to install home circuit. Can you calculate the resistance of this coil? (P
Xiaoqiang bought a coil of 100 meters long and 2 mm in diameter copper wire to install home circuit. Can you calculate the resistance of this coil? (P copper = 1.7 times 10 to the minus 8 ohm. M)
R=p×L/S
=1.7 × 10 to the negative 8th power × 100 / (π × (0.001) square)
=1.7/π
≈0.54Ω
Xiao Li's house was decorated. He bought a coil of 100m 2.5mm ^ 2 copper wire to install a special line to supply power to the air conditioner with rated power of 1.5KW. In fact, half of the wire was used. If the air conditioner can work normally, what is the voltage loss on this section of wire? The resistivity of copper is 1.7 × 10 ^ - 8 Ω· M
According to r = resistivity of copper * conductor length / cross-sectional area
It can be found that r = 3.4 * 10 ^ - 3 Ω
From P = IU
I = 1500-220 ≈ 7 (voltage according to 220 of household appliances)
Therefore, u circuit = IR = 3.4 * 10 ^ - 3 * 7 = 2.38 * 10 ^ - 2
In the activity of how to make a small light bulb light up, Xiao Li connects the small light bulb, dry battery and switch with wires. When the switch is closed, the light bulb doesn't light up. After a while, the battery heats up. The fault of this circuit is ()
A. The bulb is broken. B. the battery is dead. C. open circuit. D. short circuit
The battery is hot, indicating that there is current in the circuit, and the circuit breaker is eliminated. However, the small bulb does not emit light, the fault is D, and the power supply is short circuited
The conversion relationship between the attraction of the open electromagnet and the cross-sectional area, turns and voltage of the conductor
Good question!
In fact, the attraction of electromagnet is related to many factors, such as the current I, the number of turns of coil W, the length L of air gap in the whole magnetic circuit and the sectional area s of air gap
We know that the magnitude of the suction is related to the effective flux Φ of the electromagnet
That is, f = (Φ / 5000) ~ 2 * 1 / s. therefore, as long as the effective magnetic flux Φ of the electromagnet is calculated, the suction of the electromagnet can be calculated. Therefore, the problem is converted to the calculation of magnetic flux Φ
The solution is as follows
Because the magnetoresistance of the magnetic circuit RM = L / μ s, and IW = Φ * RM, the problem is transformed into solving the magnetoresistance of the magnetic circuit. This problem is the focus of our whole problem. The solving process of the magnetoresistance of the magnetic circuit is a very complex process, and the solving process of the magnetoresistance is different with different kinds of electromagnets
So now your question is not very complete, I can only answer here
About electromagnet design. I have a book in my hand. Give me an email and I'll send it to you
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