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Four practical questions on how many points to get
1. Xiao Ming is 1 / 12 taller than Xiao Jun, and Xiao Jun is 12 cm shorter than Xiao Ming. How many cm is Xiao Ming?
2. Use the rope to log the well depth. Fold the rope three times to measure it. It is 2 feet away from the bottom of the well. Fold the rope two times to measure it. If it is more than 1 / 4 of the well depth, how many feet is the well depth
3. After two thirds of the total length of a highway is completed, it is 16.5km away from the midpoint. How many kilometers is the total length of this highway?
4. The apprentice made 2 / 7 of the total parts, 21 less than the master. How many parts are there in this batch?
5. In a workshop, the number of absentees in the morning is 1 / 7 of the number of attendants, and in the afternoon, another one asks for leave to go home, so the number of attendants is just six times of the number of absentees. How many workers are there in this workshop?
6. The school uses 40 meters long iron wire (excluding the joint) to form a rectangular vegetable field. It is known that the width of the rectangle is 1 / 4 of the length. What is the area of this vegetable field in the school
7. If you sell a coat for 100 yuan, you can make 1 / 4 of the money
8. When the first and second bags of rice are poured out by 1 / 10 to the second bag, the weight of the two bags of rice is equal. How much more is the first bag of rice than the second bag?
9. The distance between a and B is 1152km. A passenger train and a freight train run from the two places at the same time. The freight train runs 72km per hour, 2 / 7 faster than the passenger train. How many hours do the two cars meet?
RT: Xiaoming's father is on a business trip for five days. The total number of the five days is 35! Xiaoming's father comes back from the fifth day of business trip. What's the date of the day when Xiaoming's father comes back?
Attention upstairs is the primary school application problem Equation god horse of course is the most annoying~
(35 △ 5) + 2 = 9
Cut a circle with a radius of 4cm into several equal approximate isosceles triangles along the radius, and then put them together into an approximate rectangle. The length of the rectangle is () cm, the width is () cm, and the area is () cm?
Cut a circle with a radius of 4cm into several equal approximate isosceles triangles along the radius, and then put them together into an approximate rectangle. The length of the rectangle is (12.56) cm, the width is (4) cm, and the area is (50.24 square cm)
What role does resistance play in AC circuit
It depends,
NTC resistors in series play the role of "current insurance" in AC circuit
The parallel connection of varistors in AC side circuit mainly plays the role of "limiting the ultra-high voltage"
RELATED INFORMATIONS
- 1. The correct statement about conductor resistance is () A. Because the resistance of the conductor indicates the resistance of the conductor to the current, when there is no current in the conductor, the resistance of the conductor is zero. B. the greater the voltage at both ends of the conductor, the greater the current, so the resistance of the conductor decreases with the increase of the voltage. C. the resistance of the conductor is the property of the conductor to block the current, and its size has nothing to do with the voltage and current intensity The greater the voltage at both ends of the conductor, the greater the current, so the resistance of the conductor increases with the increase of voltage
- 2. What are the functions of resistance, current, voltage and relay in the circuit
- 3. To explore the relationship between current and voltage through the conductor, how to keep the resistance constant when the sliding rheostat changes the voltage in the test To explore the relationship between current and voltage through the conductor in the test Slide the rheostat to change the voltage. I know, but when you move the rheostat, the voltage changes and the resistance changes Why can the resistance remain unchanged? The length of the current has changed
- 4. In the experiment of exploring the relationship between the current through the resistance and the resistance value, the function of sliding rheostat is_____
- 5. 1. When moving the slide of the sliding rheostat, which two terminals will change the resistance? Which direction will the resistance increase? 2. In order to turn the bulb from dark to light, where should the slide of the sliding rheostat be placed before connecting the circuit?
- 6. What is the change of the total resistance during the movement of the sliding rheostat in the divider circuit? Tell me why
- 7. In sliding rheostat, AC, BC, BD and ad move R (resistance) and I (current) in P direction?
- 8. How to choose the connection method of sliding rheostat for measuring resistance by voltammetry?
- 9. What is the function of sliding rheostat in measuring resistance by voltammetry
- 10. Physical electricity: measuring the resistance of a small bulb, Now you don't have an ammeter. You only have a voltmeter, a sliding rheostat, a 10 ohm quantitative resistor, a 6V power supply, a switch and several wires. At this time, you can't measure the resistance of a small bulb by volt ampere method. What's the resistance of a small bulb? You need a circuit diagram,
- 11. 4 Calculation questions Zero - half - (minus three fourths) + (minus five sixths) - two thirds |Negative two and a half | - (- 2.5) + 1 - | - 1-two and a half| 13-[26-（-21）+（-18）] [1.4-（-3.6+5.2）-4.3]-（-1.5） We need a process. Thank you
- 12. Calculation of atmospheric pressure For a pressure cooker with a diameter of 20cm, the cross section of the vent is 10mm ^ 2. If the maximum pressure of steam in the cooker is 1.7 * 10 ^ 5pa, what is the mass of the pressure limiting valve? (set the external pressure as 1 * 10 ^ 5pa)
- 13. Very simple score calculation problem Oh, help to calculate, OK One eighth multiplied by two is equal to one Twelve times three eighths is equal Eight out of twenty-five divided by four out of five equals Four fifths divided by three fifths is equal to four fifths Two divided by two thirds is equal to two Two out of eleven times eleven out of four is equal to one Four ninths divided by three fifths is equal to three fifths Five eighths divided by five twelfth equals five Half of a thirtieth divided by a quarter equals half
- 14. 1. The fruit store brought in 180 kg of fruit, sold 2 / 5 of the fruit on the first day, and sold the remaining 3 / 4 the next day. How many kg of fruit are left? 2. The school canteen bought a barrel of oil, which weighs 24 kg. The first time it used 1 / 4 of the total oil, the second time it used the remaining 1 / 3, and the third time it used 1 / 2 of the oil in the barrel. How many kg of oil is left in the barrel?
- 15. How many ohm resistor should be connected to 120 white LED lamps connected to 12 volt dry battery? The voltage will drop if there are too many
- 16. What is the resistance value of a resistor when a voltage of 10V is applied at its two ends and the current is 0.5A?
- 17. When a fixed value resistor is applied with 10V voltage at both ends, the current is 0.5A. If the voltage at both ends of the resistor is 0, what is the resistance value?
- 18. The two lamps are connected in parallel, the known resistance R1 = 5 ohm, the main circuit current I = 0.5A, the voltage at both ends of R2 U2 = 2V, and the circuit current I = 0.5A The two lamps are connected in parallel, the known resistance R1 = 5 ohm, the driving current I = 0.5A, and the voltage at both ends of R2 U2 = 2V 1. Find the current through R1 2. Current through R2 3. Resistance of R2 It's a process. Thank you
- 19. How to know which electric current is measured by ammeter? I know which consumer the ammeter is connected in series with is to measure which consumer's current, but I just can't tell which consumer the ammeter is connected in series with. I don't know whether it's left or right!
- 20. The voltage at both ends of a circuit is 220 V, and the resistance of the consumer is 40 Ω. Can we use an ammeter with a range of 0 ~ 3a to measure its current?