How to understand these two sentences, the best explanation is easy to understand Density is a property of matter, which has nothing to do with the mass and volume of the object. We can't think that the density of matter is directly proportional to the mass and inversely proportional to the volume. Why not? How to understand the meaning of these two sentences? The best answer is easy to understand

Density (d), volume (V) and mass (m) are the relations of "three variables", that is, d = m / v. therefore, if we want to talk about the relationship between the two variables, we must also consider the third variable
As you mentioned, "the density of an object is directly proportional to its mass" is hard to judge whether it is true or not, but if you add a precondition in front of it, it will be true
When the volume of an object is fixed, its density is proportional to its mass
Similarly, if the other sentence is changed to
It is also true that when the mass of an object is fixed, the density of the object is inversely proportional to the product

Do not understand the meaning of this sentence, please explain!
"Tea said: I'm just a glass of water. All I can give you is your imagination. What you think is what you want." if this is what friends say, what do you mean?

A lot of things are just self deception

The proverb about reading (which few people know), and the explanation of this sentence

A bulb (considering the effect of temperature on resistance) is connected to the rated voltage, and whether the current passing through it is equal to the rated current
Give reasons

At the beginning, the filament temperature is low and the current is large, which is commonly known as impulse current. However, with the work and heating of the current, the filament resistance increases and the current decreases. The current reaching the normal value is the rated current

What is hook 3 strands 4 strings 5

At the beginning of Zhoubi Suanjing, one of the earliest mathematical works in China, records a dialogue in which the Duke of Zhou asked Shanggao for mathematical knowledge. The Duke of Zhou asked: "I heard that you are very proficient in mathematics. I want to ask: there is no ladder to go up in the sky, and there is no ruler to measure the earth. So how can we get information about

Why should ammeter and voltmeter choose small range to measure resistance of small bulb
Such as the title

Small bulb resistance is small, in order to read accurately, the pointer deflection is generally required to be more than half of the dial, so the ammeter and voltmeter should choose a small range

How to do the equation of 8x + XX = 56

8x+x²=56
x²+8x+16=56+16
(x+4)²=72
x+4=±6√2
x=-4±6√2

As shown in the figure, the voltage at both ends of the power supply does not change, and the resistance value of resistance R1 is 2 Ω. Close the switch S. when the slide P of sliding rheostat is at point a, the indication value of voltmeter V1 is 4V, and that of voltmeter V2 is 10V. When the slide P of sliding rheostat is at point B, the indication value of voltmeter V1 is 8V, and that of voltmeter V2 is 11V. Then the resistance value of resistance R2 is 4V___ Ω．

According to the constant total voltage, the sum of the indication of voltmeter V2 and the voltage at both ends of R1 should be the power supply voltage. The sum of the indication of voltmeter V1 and the voltage at both ends of resistance R2 is also the power supply voltage. According to the equal power supply voltage, the following equation can be obtained: 10V + i1r1 = 11V + i2r1 ①4V+I1R2=8V+I2R2… ② To turn into

Given x ~ t (n), we prove that X & # 178; ~ f (1, n)

T (n), so x = X1 / radical (Y / N)
X1~N(0,1) Y=Y1²+Y2²+…… +Yn² Yi~N(0,1)
So x & # 178; = (x1 & # 178 / 1) / ((Y1 & # 178; + Y2 & # 178; +...) +Yn²)/n)
So x & # 178; ~ f (1, n)

Voltage 220 V, power consumption 3000 w / h (3KW / h), how much is the current?

The power is 3KW
P/U=I=3000/220=13.6A
This is the pure active current (the power factor is considered as 1). If the nonlinear load is used, it needs to be divided by the power factor

Do not understand the meaning of this sentence, please explain! "Tea said: I'm just a glass of water. All I can give you is your imagination. What you think is what you want." if this is what friends say, what do you mean?