Why is the edge of the glass coffee table polished smooth, explained by physical knowledge?

The edge of the glass coffee table is equivalent to the contact area with the human body, and the edge of the glass coffee table is ground to be smooth, which is actually an increased contact area, so as to prevent the human body from being injured when it touches the edge of the coffee table, and in the case of an increase in the contact area, the same strength reduces the pressure.

Physical significanceThe amount of friction has nothing to do with the contact area, and is proportional to the actual contact area, and the actual contact area is proportional to the pressure, so the actual contact area of the solid substance to the ground is equal regardless of whether it is placed horizontally or vertically.

The glass coffee table is generally used to drink tea, and the water in the thermos is boiling. Boiling water will cool down quickly after being poured into the coffee table.

Imagine that when people drink tea, their mouths must be in contact with the coffee table, and the coffee table must be smooth at this time, and the personal feeling must be good. Unless it is necessary to make it rough, but in fact it is not necessary! Chemically, the mouth of some bottles containing reagents is rough, which is to change the concentration of the reagent in order to prevent the reagent from volatilizing, and of course, some reagents are corrosive to make them rough.

The cup coffee table is really not necessary, and it may cause the pressure inside the cold water cup to become smaller, and there is a pressure difference between the pressure outside the cup, making it difficult to open the cup.

The molecular spacing is greater than 10 times the diameter, and the intermolecular repulsion force is greater than the gravitational force.

What grade are you in? According to the second law of thermodynamics, the entropy of broken glass will not decrease during spontaneous generation, and the entropy value of broken glass is greater than that of intact glass.

Oh, in fact, this physics is actually a matter of friction, because the friction in this place is small, so in this case, many of his properties can't be represented, and they don't conform to the basic road conditions.

It is unsafe, mainly because the tires are slippery, which is equivalent to playing on a flat ice surface, and the ground does not have much friction coefficient, which is prone to accidents!

(1) In the process of propagating light along a straight line, it encounters an opaque object and cannot propagate, forming a black outline behind the object, which is the formation of shadows;

2) Plane mirror imaging is formed by the reflection of light;

3) The mirage is formed by the deflection of light in the direction of light propagation in the atmosphere with uneven density, raft destruction and even dusting, which belongs to the refraction of light.

4) When sunlight passes through the prism, it will be decomposed into seven monochromatic lights: red, orange, yellow, green, blue, indigo, and violet, which is the dispersion phenomenon of light

So the answer is: (1) light travels in a straight line; (2) reflection of light; (3) refraction of light; (4) Dispersion of light

It's as if the windows of a car are all glass. And it is tempered multi-layer laminated glass. The car is driving at high speed. The windows need to withstand a certain amount of pressure.

I didn't explain the problem, at least I completed it.

There are two reasons for this.

1.The formula according to the power is p=fv

Because the power must be constant when the car is moving.

Then reduce the velocity v.

The traction force f went up.

It's easy to go uphill.

2.The mass of the car is comparatively larger.

The state of movement is not easily changed.

If the speed is too large.

And the mountain road is rugged.

In case of any sudden accident, it is not easy to brake and stop immediately.

This can lead to traffic accidents.

Something ,,, open the window to drive the air flow and take it out, it's as simple as that. The air pressure in the house is relatively stable, and the outside of the house is certainly not as stable as the inside of the house because of the wind, so it should be replenished at any time.