Have a few physics questions you d like to ask? Need answers?

1.Uranium is used because it is easier to happen, and the reaction can be transmitted, which is what is called the chain reaction upstairs, one collision is done and then it hits the next, you can encyclopedia the chain reaction.

2.You're right, this question falls under the category of definitions.

3.The transformation of an atom into an ion is the reason for the loss of electrons, and the charge of electrons and nuclei is constant. The electrons are negatively charged, and the electrons are positively charged. The charge charge of an electron is -e, i.e. a negative meta-charge, which is a fixed amount.

Regarding your question upstairs: neutrons and protons can be divided into quarks, and electrons have not yet been found to be divided into quarks, but it is not certain what will be discovered in the future.

Einstein's formula corresponds energy to mass, and splitting to the limit does not mean that the mass will become 0, but it does release energy. The conversion is the nuclear binding energy, which is δmC2. But it doesn't have to be all converted into energy.

If it is really possible to divide to the limit, even if the mass of each ingredient becomes close to 0, the quantity becomes infinite. It is still possible that the total mass exists.

Also, I don't know how old you are now, but these high school physics and chemistry you ask will be taught.

In response to your first question, you can see that you are a thoughtful and creative person. However, nuclear fission is conditional, and not all matter can be. Even uranium is a material that has nuclear fission, but it is easier to produce nuclear fission than other materials.

It is recommended to take a look at the section of the high school physics book about "Atomic Physics".

In response to the second question, I would like to say that chemical reactions are not all based on atoms, and different combinations of atoms can produce new substances, but after atoms lose or gain electrons, they become ions. There are also many physical phenomena that may be accompanied by chemical reactions.

The atom loses its electrons and becomes positively charged, and the electrons obtained become negatively charged and become ions, but without changing the structure and content of the nucleus (protons and neutrons), the nucleus is still positively charged, and the electrons are still negatively charged, and the charged properties have not changed!

I hope my answer will be useful to you, I still have something to do, so that's all for now!

1.Of course, the atoms of those substances can also be used, but it is necessary to consider how easy it is to fission, uranium is easily fissioned by neutron impact, and it can be carried out in a chain reaction.

2.All chemical reactions are based on the smallest unit of atoms, and a change in the nucleus of an atom is already a physical change.

3.The nucleus of an atom is positively charged, and the electrons outside the nucleus are negatively charged, which is constant, and the chargeability of ions is manifested due to the fact that the charge charge of the nucleus is not the same as that of the electrons outside the nucleus.

Question 2. The last sentence is not correct, it is not a physical phenomenon, but it is classified separately.

1.Reflect objects in the car below the driver to avoid accidents.

2.The air above the flame is heated coarsely or unevenly, and the refractive index of the light is different.

This is a very simple question:

Do a force analysis (unfortunately can not paste **, I have to describe it in the text, I hope to make some improvements, for physics lovers to mention the blind shirt Zen for a little convenience) object on the inclined plane by four forces, gravity, support force, tension, friction, in the direction of the vertical inclined plane, gravity along the direction of the component and the support force balance, the list can find the size of the support force, and then find the friction force, it is equal to the friction coefficient and the positive pressure (that is, the reaction force of the support force, the magnitude is of course equal to the support force). The difference between the tensile force and the frictional force (or algebraic sum) is the force of the object to accelerate the motion on the inclined plane, and then the acceleration can be calculated according to f=ma (the specific value is calculated by yourself, the physics lies in the process, and the collapse pin is the result of miscalculation and only a small number of points will be deducted).

The second question: There are two simple methods: first, if you have learned the impulse theorem, use the impulse theorem, and grind the dust in one step. ft2=m

v2-v1) in this case, f is the frictional force, v1 = 0, v2 = at1 (the corner mark is to distinguish that t in the two equations is not the same he, t1 is 2s, and a is a obtained in the first question). The second method is to use kinetics. In this case, only the frictional force is applied along the inclined plane, and the acceleration A2 can be found according to F=MA2, which is the same as in the first solution according to A2T=V2-V1, V2, V1.

3. The two stages of the process are uniform acceleration motion, the difference is that the acceleration is positive and the other is negative. It can also be done with the kinetic energy theorem.

20cm=

The average speed is equal to.

Acceleration is equal to 2-1 (

The average velocity is equal to the instantaneous velocity at the midpoint of time.

This should be a is the first ball A before there is no ball.

D and C are 30 cm apart

A

1.A train travels at a speed of 30 meters per second on a straight track, and a 300-meter-long freight train at a speed of 20 meters per second is approaching a passenger in the window seat as it passes in front of her eyes (d).

Seconds seconds.

2.Regarding the uniform linear motion, the following statement is false (b).

a.Motion that does not change the speed or direction of motion is a uniform linear motion.

b.The speed of the movement does not change, and it is a uniform linear motion.

c.Motion that follows a straight line and travels an equal distance in equal time is called a uniform linear motion.

d.Motion that moves in a straight line and the ratio of distance to time remains constant is called uniform linear motion.

3.The fastest sailfish swims in the water, reaching speeds of up to 108 km/h; The fastest cheetah on land can run 40 meters in 1 second; The fastest brown petrel in the air, which can fly 5 kilometers in 1 minute, compare their speed (c).

a.Cheetah speed max bSailfish speed max. cBrown petrel has a maximum speed of dAll three are equally fast.

Explanation:1The combined speed of the two trains is 50 meters per second, and the time is: 300 divided by 50 to 6 seconds.

2.Review the formula for uniform linear motion.

3。Unit conversion questions: Sailfish: 30 meters per second, Cheetah: 40 meters per second, Petrel: 99 meters per second.

The lens of the camera is equivalent to a convex translucent lens (convex transparency), the distance to the object is the object distance, and the distance from the lens to the image is the image distance, and an inverted and reduced real image can be obtained on the negative, and the object distance should meet the conditions other than 2 times the focal length.

A magnifying glass is a hallx lens. When using a magnifying glass, the object should be placed within 1x focal length to be able to obtain a magnified upright image.

The lens of the camera is equivalent to a concave lens (convex transparency), the distance from the object to the focal length is the object distance, and the distance from the lens to the focal length is the image distance. When using a magnifying glass, the object should be placed within a double focal length to obtain an upright, magnified virtual image.

The relationship between fluid pressure and flow velocity.

Raid 1In the vicinity of the earth's surface, every 10m elevated, the atmospheric pressure decreases by 100pa, and the atmospheric pressure is measured to the fifth power of the PA from the airplane flying in the sky, and the atmospheric pressure on the ground is 1*10 to the fifth power of the PA, from which it can be seen that the flight altitude of the aircraft is 1000 When a tornado occurs, the atmospheric pressure outside the house drops sharply to the power of 90*10 PA; At that time, the doors and windows were closed, and it could be assumed that the area of the roof in the house was 100m square, and the pressure difference between the inside and outside of the roof could reach 100,000N, which was enough to tear the roof over. 3.

When mainland tourists first arrive on the Qinghai-Tibet Plateau, they will experience dizziness, tinnitus, and even vomiting, the main reason is that the air on the Qinghai-Tibet Plateau is thin and the atmospheric pressure is less than the optional "greater than", "equal to" or "less than") one standard atmosphere. The instrument that measures atmospheric pressure is called a barometer 4

After heating for 3 5 seconds with the mouth of the test tube facing down, it is placed above the flame of the alcohol lamp, and then immediately inserted vertically into a certain depth in the container containing water. (1) You guess that the phenomenon that may occur is that water is sucked into the test tube, and 2) you guess that the air pressure in the test tube becomes smaller

On the premise that the data you give is okay, the answer is as follows.

1000, to the seventh power n, less than, barometer, the water surface in the test tube rises, and the air inside the heated test tube expands by heating"Run"When part of it goes out, the air pressure decreases, and the liquid level rises under the action of the outside atmospheric pressure.

1000m, 10 to the 6th power n, less than, barometer, after a while the water surface in the test tube is higher than the water surface outside the test tube, after inserting into the water, the heated gas is cooled to cause the gas pressure in the test tube to become smaller, and the gas pressure on the water surface remains unchanged, and the pressure difference presses the water into the test tube.

(!1000, (2) 100000pa, 1000000n (3) less than the barometer The liquid level in the tube rises and the air expands and contracts.

It is determined by the momentum theorem fcos t=mv and the average power in ts p=w t=mv 2 2t, and the instantaneous power p'=fcos v at ts

The average power p=(fcos t) 2 2m

Instantaneous power p' = fcos v = (fcos ) 2t m