Problems of the kinetic theory of physics and the law of gases

Hehe, it's been a long time, it's a rare memory!

1.The order of magnitude is made by scientific notation, too, 6370km, too.

To the sixth power, so the answer is the negative power of ten and the sixth power of ten.

2.I forgot the name of the specific phenomenon, but most of its rates are around a certain value (average or overall performance). As for the second void, it is increasing or increasing.

3.Brownian motion was originally an experiment in which Brown observed pollen in water with a microscope, and how many molecules the pollen had to make, so the first statement was wrong, but in essence, Brownian motion is the result of molecular motion.

For the second and third questions, you can use pollen experiments as an example, the movement of pollen is caused by the impact of water molecules, water molecules from all sides of the pollen, up and down, left and right to hit the pollen, the smaller pollen will be hit by the water molecules unbalanced (or the pollen symmetrical position is hit by the number of water molecules is different), so it will move, and the larger pollen, the symmetrical position of the collision will reach a certain balance, so the movement will not be obvious (there are some personal understanding, That is, even if the symmetrical position is hit by the same amount of difference, due to inertia, the smaller one will always be more significant).

In addition, there are some suggestions for you personally, you should read more textbooks for learning, and understanding the knowledge in the books is the first priority, and the questions you ask can be said to be conceptual problems in the textbooks, or a little understanding. If you really want to improve your grades, especially in physics, understanding is more important than doing problems, which is one of the reasons why some people don't seem to have learned much, but their grades are very good.

1 The diameter of a table tennis ball is, and its order of magnitude is 10 (-2) m; The radius of the Earth is 6370 km, and its order of magnitude is 10 (-6) m (why do you have a process).

2 Molecules are doing irregular thermal motion, for a large number of molecules, the velocity of the molecule follows a certain statistical law, and the velocity of most molecules is around a certain vertical" phenomenon, and as the temperature increases, the number of molecules with a larger velocity accounts for the proportion of the total number of molecules

3 Is it true to say that "Brownian motion is molecular motion"? Why is the smaller the Brownian particle, the more significant the Brownian motion? If the particles are too large, they won't show Brownian motion, why? Let me give you an example.

Law 1: Boyle's law: The pressure of a certain mass of gas is inversely proportional to its volume when the temperature is constant. Specific formula:

p1/p2=v2/v1

orp1v1=p2v2

PV = constant. Because PV = constant, the image is a hyperbola.

Law 2: Charlie's Law: For every increase (or decrease) in temperature of a gas of a certain mass with the same volume, the pressure increased (or decreased) is equal to 1 273 of its pressure at 0. Specific formula:

pt-p0)/t=p0/273

orpt=p0(1+t/273)

orp1/t1=p2/t2

The characteristics of this law: the volume does not change, the temperature changes.

Law 3: Guyusac's law: The volume of a gas of a certain mass is proportional to the thermodynamic temperature under the condition that the pressure is constant. Specific formula:

v1/t1=v2/t2

The law is characterized by constant pressure.

From the above three laws, the following can be obtained: the ideal gas equation of state p1v1 t1=p2v2 t2

orpv t = constant.

orpv=nrt...n: number of moles of gas; r: constant).

Imagine there's a plastic bag that traps all the air that's going to go into the sprayer.

So the gas is in its initial state.

p1=1atm

v1=（ l

After the sprayer is injected, the air volume becomes.

End state. p2=4atm

v2=according to Boyle's law p1v1=p2v2

Solution n=18

Boyle's law: p1v1=p2v2

Set the number of pumping times to x

1*(x=18

I guess you're asking about the following physical models:

1.If the lightweight spring is fixed to the wall on one side and pulls it with 40n force at the other end, then the elastic force on the spring is 40n (if the wall is not pulled away, hehe).

2.The light spring is on the vertical plane, hanging 1 weight below, the weight is 100N, and the spring is pulled with a force of 40N above the spring, then the elastic force on the spring is still 40N, and the weight will be subjected to the gravity of 100N and the elastic force of 40N in reverse, and the downward acceleration movement is done under the action of 60N resultant force (under the condition of constant upper tension).

3.The light spring is on the vertical plane, hanging 1 weight below, the weight is 100N, and the spring is pulled with a force of 140N above the spring, then the elastic force on the spring should be 140N, and the weight will be subjected to the gravity of 100N and the elastic force of 140N in reverse, and do upward and uniform acceleration movement under the action of 40N resultant force (in the case of constant tension above).

4.The light spring is hung with a heavy object above and a heavy object below, and the spring is not stressed in the air, and the answer is given according to the analysis of the question after landing (generally this kind of problem does not require solving the spring elastic force, but mostly combines the functional relationship to solve the speed change and deformation, etc.).

It can be seen that the elastic force on the lightweight spring is only related to the tensile force and pressure it is subjected to, which actively causes the follower, and the driven leads to the passive, so it is necessary to pay attention to distinguishing the active from the passive.

If you still have questions, you can ask them.

The force on both sides of a spring must be the same. Therefore, it is impossible to use a force of 100 N on the left and 40 N on the right. (in terms of knowledge now).

Try that spring and you'll find out.

If you pull 100 N on the left, if you have a pull force on the right, it must be 100 Ox. Elongation = 100 k

The situation you said should not exist, unless the spring has mass, but this situation is not studied in high school physics, and it is important to figure out the definition of spring elasticity, which is equal to the product of the stiffness coefficient of the spring and the deformation. Normally, the magnitude of the spring force is calculated based on the balance.

To answer this question, you need to master: a certain mass of gas, when the temperature is constant, the larger the volume, the smaller the pressure Answer: The analysis can draw a conclusion: a certain mass of gas, when the temperature does not change, the larger the volume, the smaller the pressure.

Therefore, the answer to this question is: the volume of gas in the glass tube decreases and the height of the mercury surface in the glass tube increases.

Comments: This question mainly tests students' understanding and mastery of the relationship between gas pressure and volume, and is a basic question

The pressure of the gas in the tube is equal to the atmospheric pressure Xinqing Qiang, and the height difference between the inside and outside of the mercury is reduced, and the internal and external pressure can not be balanced.

Since the iron ball and the wood ball can sink together at a uniform speed, the system is subjected to zero net external force and the momentum of the system is conserved, so there is.

m+m)v。=mv

So v=(m+m)v. /m

Is there any friction between the table top and the floor? If there is any, there is an external force in the horizontal direction and the momentum is not conserved.

If the ground is smooth, the momentum of the system composed of the table, the ball, and the object is conserved, and if the ball and the object do not move, the table must have velocity. Otherwise, momentum is not conserved. Satisfied.

As long as the ball rolls down from the same position of the same chute each time, the energy lost by the ball is the same each time, and the speed at which the ball reaches the end of the chute is the same, so whether the chute track is smooth or not has no effect on this experiment.

Actually, if you think about it, if you change the smooth track to a rough track, if you want the ball to reach the end of the chute at the same speed, you just need to move the position where the ball starts to release up the appropriate distance.

The ball is not smooth every time it slides down, and the energy lost is the same.

There's something wrong with your train of thought.

The total momentum after the collision is not necessarily 0

The total momentum after the collision should be 0, which is not equal to the rest of the object.

m(ball)*v(ball)=m(object)*v+m(ball)*v=0 This is a completely inelastic collision.