A cuboid glass jar, measuring from the inside, 50 cm long, 40 cm wide and 20 cm high. Now pour 1 liter of water into the glass jar, and the water depth is 100 cm______ Cm

A cuboid glass jar, measuring from the inside, 50 cm long, 40 cm wide and 20 cm high. Now pour 1 liter of water into the glass jar, and the water depth is 100 cm______ Cm

1 liter = 1 cubic decimeter = 1000 cubic centimeter, 1000 ÷ (50 × 40) = 1000 ÷ 2000 = 0.5 (CM). Answer: the water depth is 0.5 cm, so the answer is: 0.5

For the existing empty cuboid container a and the cuboid container B with a water depth of 24 cm (as shown in the figure), part of the water in container B should be poured to a, so that the water height of the two containers is the same. At this time, how many cm is the water depth?

Let the water depth of two containers be the same as x cm. According to the meaning of the title, the equation can be obtained as follows: 40 × 30 × x + 30 × 20 × x = 30 × 20 × 24, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 1200X + 600X = 14400, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp

When an electric lamp is connected to a 220 V power supply, its power is 100 W. if the power supply is connected to a long wire and then connected to the lamp, its power is 81 W, then the power consumed on the wire is 100 W______ W．

According to P = u2r, the resistance of electric lamp: r = u2p = (220V) 2100W = 484 Ω, when the power of bulb is 81w, the voltage at both ends: u = P = 81w × 484 Ω = 198v, ∵ the current in the series circuit is equal, ∵ the current in the circuit: I = u = r = 198v484 Ω = 922a, ∵ the total voltage in the series circuit is equal to the power distribution

In the quadrilateral ABCD, the degree of ∠ B is a 70 ° B 80 ° C 120 ° d130 ° if ∠ a + ∠ C = 160 °

Exclusion method a ∠ B 70 ∠ C 70-60 = 10 ∠ a 160-10 = 150 150 + 70 + 10 = 230b ∠ B 80 ∠ C 80-60 = 20 ∠ a 160 - 20 = 140 20 + 140 + 80 = 240C ∠ B 120 ∠ C 120-60 = 60 ∠ a 160-60 = 100 60 + 100 + 120 = 280d ∠ B130 ∠ C 130-60 = 70 ∠ a 160-70 = 90 + 70

It is known that the open circuit voltage is 120V and the resistance is 0.2 ohm. After the load is connected, the power supply drops to 100V and the resistance value of the load resistance is calculated

When the power supply is connected to the load, the voltage decreases to 100V. That is to say, the internal resistance of the power supply consumes 20V voltage, 20 / 0.2 = 100A. This is the current in the whole circuit. 100V / 100A is the resistance value of the external resistance, which is 1 ohm

Solving problems with mathematical equation of one variable and one degree,
A truck drove from a place to B at a constant speed. Two hours later, a car set out from a place to chase the truck. The speed of the car was 30 kilometers higher than that of the truck per hour. However, the car ran into a fault after driving for one hour. After 15 minutes of repair, it went on the road to chase the truck, but the speed slowed down by a third. As a result, it took another two hours to catch up,

25 V = (V + 30) × 1 + 2 × (V + 30) / 3

220 V voltage, with 1000 watts of electrical appliances, how big is the current? How to calculate?

I = P / (V * cos φ) you didn't say what the electrical appliance is, so you don't know the power factor. You can calculate it by yourself according to the formula. The current should be between 4.55 and 6.5 amperes

Given sequence an satisfies A1 = 1 / 2, an + 1 = an + 1 / N & # 178; + N, find an

a(n+1)=an +1/(n²+n)=an +1/[n(n+1)]=an +1/n -1/(n+1)
a(n+1) +1/(n+1)=an +1/n
A 1 + 1 / 1 = 1 / 2 + 1 = 3 / 2, and the sequence {an + 1 / N} is a constant sequence whose every item is 3 / 2
an +1/n=3/2
an=3/2 -1/n

When 58.5g NaCl is dissolved in 1L water, the concentration of substance is 1mol / L, why 500ml 0.5mol · L-1 CuSO4 has 40g, why
Isn't that 40.25

[question 1]: the mass concentration of substance (mol / L) = the mass of solute (mol) / the volume of solution (L) 58.5g, the mass of NaCl is 58.5g △ 58.5g/mol = 1mol, the volume of solution is the volume of water (1L) + the volume of NaCl solution ≠ 1L, so the mass concentration of substance is not 1mol / L [question 2]: 500ml 0.5mol/l

Out of form calculation

In the calculation of mixed operation, it is usually to calculate a formula one step at a time (step-by-step calculation, the equal sign can not be written on the original formula), and the process of each step should be written. Generally speaking, the equal sign should go forward, Do not align with the first line, that is to say, leave the original formula for calculation: for example: 25 + 65 + 98 = 90 + 98 = 188
How to calculate the formula? The main thing to master is to remember to calculate multiplication and division first, and then add and subtract. In the successive calculation of multiplication and division, we should calculate from left to right. In the process of calculation, we should draw the operation sequence line according to the operation sequence, and also achieve "three checks", First, check whether the numbers and symbols copied from the book to the exercise book are correct. Second, check whether the numbers and symbols copied from the horizontal type to the vertical type of the draft are correct. Third, check whether the numbers copied from the vertical type of the draft are correct and whether there are any omissions
In the four arithmetic operations, addition and subtraction are called the first level operations, while multiplication and division are called the second level operations. The expressions containing two or more operations are usually called mixed operations. The mixed operations of addition, subtraction, multiplication and division are also called four mixed operations, It is called operation order. The four operation orders specified in mathematics are as follows: (1) if there is only operation of the same level in an expression, the operation should be carried out in the order from left to right. That is to say, the operation order of the mixed operation only including addition and subtraction or only including multiplication and division is from left to right. (2) the first to second level operation is carried out in an expression, If it contains both the first level operation and the second level operation, then the second level operation should be calculated first, and then the first level operation. That is "multiplication and division first, and then addition and subtraction", which is abbreviated as "multiplication and division first, then addition and subtraction." (3) bracket operation. If you want to change the operation order mentioned above, you need to use brackets. There are three kinds of brackets commonly used: small brackets, denoted as (); middle brackets, denoted as ()[ In a formula, if there are several kinds of brackets, we should first calculate the ones in the brackets, then the ones in the brackets, and finally the ones in the bracket. In the calculation, we should first calculate the ones in the brackets, then the ones in the brackets, and finally the ones in the bracket, Then the results and the numbers outside the brackets are calculated in the same order
In fact, it's very simple, but do you want a topic or a topic·····
1）50＋160÷40 （2）120－144÷18+35 （3）347+45×2－4160÷52
（4）（58+37）÷（64－9×5） （5）95÷（64－45） （6）178－145÷5×6+42
（7）812－700÷（9+31×11） （ 8）85+14×（14+208÷26）
（9）（284+16）×（512－8208÷18） （10）120－36×4÷18+35
（11）（58+37）÷（64－9×5） （12）(6.8－6.8×0.55)÷8.5
（13）0.12× 4.8÷0.12×4.8 （14）（3.2×1.5+2.5）÷1.6
（15）3.2×（1.5+2.5）÷1.6 （16）6－1.6÷4 （17）7.2÷0.8－1.2×5
（18）6.5×（4.8－1.2×4） （19）0.68×1.9+0.32×1.9
（20）10.15－10.75×0.4－5.7 （21）5.8×（3.87－0.13）+4.2×3.74
（22）32.52－（6+9.728÷3.2）×2. （23）（136+64）×（65－345÷23）
（24） 420+580－64×21÷28 （25）（58+370）÷（64－45）
2、 Calculation with ladder equation
⑴6.9＋4.8＋3.1 ⑵ 0.456＋6.22＋3.78 ⑶15.89＋(6.75－5.8）×6
⑷4.02＋5.4＋0.98 ⑸5.17－1.8－3.2 ⑹ 13.75－(3.75＋6.48)×6
⑺3.68＋7.56－2.68 ⑻7.85＋2.34－0.85＋4.66 ⑼35.6－1.8－15.6－7.2
⑽3.82＋2.9＋0.18＋9.1 ⑾9.6＋4.8－3.6 ⑿ 7.14－0.53－2.47
⒀5.27＋2.86－0.66＋1.63 ⒁13.35－4.68＋2.65 ⒂73.8－1.64－13.8－5.36