Can someone give me a concept of mechanical friction

Can someone give me a concept of mechanical friction

Friction force definition: when there is positive pressure between two contacting members, the tangential resistance that prevents the two members from moving relative to each other
This content is approved and promulgated by the national science and technology terminology examination and Approval Committee
Friction is a kind of physical force exerted by two objects which are in contact with each other when they are moving. Generally speaking, objects are also subject to friction when they are moving in liquid and gas

The historical significance of the establishment of Newtonian mechanics

Newton's mechanical system, which is composed of three laws of mechanical motion and the law of universal gravitation, correctly reflects the objective law of low-speed motion of macro objects. It generalizes the laws of motion of objects on the earth and celestial bodies, which used to be completely unrelated, into a unified theory, and realizes the first theoretical synthesis of natural science, Newtonian mechanics is the foundation of the whole physics and astronomy, and also the theoretical basis of all modern machinery, civil engineering, transportation and other engineering technologies

The three basic units in mechanics are______ ．

The three basic physical quantities of mechanics are length, mass and time. Their units are kilogram, meter and second. So the answer is kilogram, meter and second

The available instruments for measuring the three basic mechanical quantities specified in the international system of units are ()
A. Meter ruler, spring dynamometer, stopwatch B. measuring cylinder, balance, stopwatch C. meter ruler, dynamometer, dot timer D. meter ruler, balance, stopwatch

Length, time and mass are the three basic physical quantities of mechanics. The meter ruler is the instrument for measuring length, the balance is the instrument for measuring quality, and the stopwatch is the instrument for measuring time. Therefore, D is correct and ABC is wrong

In the international system of units, the symbols of the three basic units of mechanics are______ 、______ 、______ ．

There are three basic physical quantities in mechanics. They are length, mass and time. Their units are m, kg and S. so the answer is m, kg and s

Three basic units of mechanics

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The three basic units in mechanics are m (meter), kg (kilogram) and S (second); they are the units of length, mass and time respectively. The rest are derived from them

How to convert atomic percentage and weight percentage?

Alloy composition is generally in weight percentage
Mass (weight) percentage of an alloy component = atomic percentage of the component*
Atomic weight of the component / (atomic percentage of each component * sum of atomic weights of each component)

How to convert mass percentage into atomic percentage in alloy, such as ti-6al-2.8sn-4zr-0.5mo-0.4si-0.1y (wt%)

Divide the mass of each element by its relative atomic mass, and the ratio is the atomic percentage

How to convert the weight percentage of ternary system into atomic percentage

Use Excel to list a row of elements, write down the formula, and then just change the elements and enter the numbers
Now my mathematics and chemistry are degenerating severely, and I'm a little afraid of degenerating
I can't think of this formula. I can convert the atomic ratio into the weight ratio;
Now my mathematics and chemistry are degenerating severely, and I'm a little afraid of degenerating
I can't think of this formula. I can convert the atomic ratio into the weight ratio;
I'm very ashamed, but I just can't figure it out. If the trouble degenerates to this state, you're finished
Degenerate to this state, you are finished
I haven't seen you for a long time. Brother phasediagram criticized me for being too LAN
As for the problem, I've thought about it
Besides, I'm also doing a lot of research on mathematics, physics and chemistry. When I'm free, I occasionally look at advanced mathematics. I also bought the Book Physical Chemistry edited by Wang zhenglie on the Internet. It just arrived today
I found that people's brain has to be used frequently, and it will degenerate if not. As long as the brain is flexible, people won't get old, and the brain needs to be used frequently. In order to keep the brain healthy, I occasionally turn the magic cube, buy some intellectual books and so on, and flip them in my spare time
Congratulations on thinking it out
It's easy to find out
Congratulations on thinking it out

Conversion percentage method of quantity proportion
For example, 4:3 is the percentage of 3, how to calculate the formula

In 4:3, the percentage of 3 is 3 / (3 + 4) = 0.4288 = 42.88%