Junior high school subject competition, how to grasp junior high school subject competition

If you really have the ability, you shouldn't give up the opportunity, I agree that upstairs, you should study chemistry, and if you win the competition, you will increase the chance of being placed in a small class in high school.

I am now in my second year of high school, and I am in a key high school, and when I go to high school, I will find that some of my classmates know a lot more about chemistry than me, and they must have learned more when they first came into contact with chemistry in junior high school.

As for winning the prize, I think you must be very smart, buy some books on this subject, it would be better if you borrowed a high school chemistry book, it is better to find an experienced teacher to give you a systematic lecture.

Finally, I want to warn you: the competition is just a side job, and the high school entrance examination is the last word. Being admitted to a key high school is better than winning several championships.

My e-mail: wang hao, if you don't understand anything about your studies, please ask me.

Participating, whether you win an award or not, is also a kind of practice. Maybe you can get a satisfactory score in chemistry in the high school entrance examination.

What is a contest?

It's not dozens of competition books, hundreds of exercises, thousands of days and nights; It's not ranking, gold medals, escorts, it's not glory, lust, and power.

So what is it?

It's a grind, it's a grind that both teachers and students will remember, can you stand this grind?

It's a pursuit, it's a pursuit that makes both teachers and students feel happy and painful, have you ever had such a pursuit?

It's a spirit, it's a faster, higher, better Olympic spirit, have you carried it forward?

It is a process, it is a process that gradually sublimates the hardships of teachers and students, have you experienced this process?

It's a complex, it's a complex that is hard to part with for life, have you ever had such a complex?

I thought, that's the competition! This is the highest level of competition, and as long as you put your heart and soul into the competition, you will reach such a state.

One is enough, more is difficult to master.

What you choose depends on what you are good at, or what you are interested in.

Personally, I recommend physics because it is easy to learn and can increase your thinking skills and make you smarter.

Yes, if you think it's easy to do your homework right now.

It's worth participating, and it's going to be a little good for yourself, so you can learn more. However, in terms of time, you have to allocate it yourself.

I have a friend who was in his third year of junior high school, and he also participated in almost any competition, and he also won awards one after another, which was very envious of me.

When you win an award, your self-confidence increases, and that's great.

It's necessary. The junior high school competition promotes high school learning.

Especially chemistry.

Because chemistry competitions are mostly ahead of their time.

So in junior high school, you can compete and you can get a lot of exposure to high school knowledge.

Yes, I believe that there must be no problem in in-class learning to ask this kind of question, and participating in the competition will lay a good foundation for high school, and at the same time prepare for the high school entrance examination, and most of them will be rewarded.

I participated in it in my third year of junior high school, won awards, and got extra points.

As long as you have a certain foundation and have initially learned some knowledge of high school, it should be possible to win the award!

Actually, there's nothing wrong with participating in competitions. And if you have more than enough energy to learn, of course, you must conduct extracurricular competition tutoring without affecting the main class.

Buy a better competition book, with analysis, explanation, and difficulty, and it is enough to finish one and read it thoroughly.

I am also in my third year of junior high school, and my teacher also asked me to have spare time to do some competition problems. But recently, I have been doing a lot of homework, and I can't take a break, and the teacher is also considerate, saying that I have time to do it.

It's better to learn than not to learn, even if you don't win a prize. After all, studying is not for winning prizes, nor for the high school entrance examination.

Strongly despise the high school entrance examination system).

It is recommended that you first calm your mind, and if you really want to take the exam, it is recommended to start with English, because the gap between the content of the small paper and the high school entrance examination is not obvious. Also, if you're not good at math (I mean compared to the competition), you might want to consider having time to do a little bit of physics and focus on sports. Of course, if you don't have traces of things, your math is okay, it is recommended that you take the college entrance examination first, and then take a look at the math problems after the exam.

Slipping at a uniform speed, indicating that the force is balanced, the hidden gravity per mu = the resultant force of the resistance when sliding, and the work done by gravity when sliding is 150j

When pulling the object from the bottom of the inclined plane to the top, it is necessary to overcome gravity and resistance, and the trembling is so = 2 times the speed of the cave hall 150j

The fastest speed of car B is that the upper left corner of car A collides with the upper right corner of car B because it has been driving along the dotted line in the middle, so when it collides, car A is far from the horizontal dashed line meter (that is, half of the width of car B), so car A is driving (m, that is, m. Because the speed of car A is 36 km/h (10 m/s), car A travels for a second. So the travel time of car B is seconds.

The distance traveled by car B is 40+ meters. The speed is meters and seconds.

The slowest speed of vehicle B is that the upper left corner of vehicle B collides with the lower right corner of vehicle A. The driving distance of car A is 30+ meters, and the driving time of car B is seconds, and the driving distance of vehicle B is meters, and the speed is meters and seconds.

So the velocity range is to.

You can think of C this way, because the speed of the two balls is 5 meters and seconds, and the distance between them is 10 meters, which is equivalent to a time difference of 2 seconds, that is, it is equivalent to the first ball of B to start, and ball A starts to start 2 seconds after the start of ball B, and then no matter what position the ball moves, but everyone always moves together, so ball A is always 2 seconds behind ball B, so the difference between the two balls is 14 meters when moving on the horizontal track CD.

Because A and B are separated by 10m, that is to say, the time difference between them and the slope is 2s, because the speed of the subsequent trajectory is the same, that is, there is a time difference, and the time they leave the slope is also 2s. There is a difference of 2 seconds when reaching any point, and at a speed of 6 m s in the CD segment, the time difference of two seconds can give B a 12 m lead. So choose C

I also need the process of this topic, but there is a question about what is written upstairs

A metal ball with a temperature of 100 is placed in container A, and when the same temperature is reached, the water temperature in container A rises by 40:

t A 40 t = 68

T-ball = (100 -68) = 32

Q put q suck.

C ball m ball t ball c water m water t a.

C ball m ball = c water m water t A t ball.

C water m water 40 32

5c water m water 4

When quickly taking out the metal ball and putting it into container B: let the water temperature in container B be t, then the ball t t-68 t B = 100 -t in the same way q put q suck.

C ball m ball t ball c water m water t b.

5 C water m water 4 (t-68) C water m water (100 -t) t

Let the specific heat of the ball be c, mass m, mass m, mass m, specific heat r of water

In the process of equilibrium in the temperature of A, the heat absorbed by the water Q1 = the heat Q emitted by the ball'

q1=40rm

q'=(100-(28+40))cm=32cmrm=

Put B, the heat released by the water Q2 = the heat Q absorbed by the ball during the equilibration process'', the final water temperature tq2=(100-t)rm=

q''=(t-68)cm

Therefore (t-68)cm=

t=148 degrees.

Let the specific heat of the ball be c, mass m, mass m, mass m, specific heat r of water

In the process of equilibrium in the temperature of A, the heat absorbed by the water Q1 = the heat Q emitted by the ball'

q1=（40-28）rm=12rm

q'=(100-40)cm=60cm

rm=5cm...

Put B, the heat released by the water Q2 = the heat Q absorbed by the ball during the equilibration process'', the final water temperature tq2 = (100-t) rm = 5 (100-t) cmq''=(t-40)cm

Therefore (t-40)cm=5(100-t)cmt=540 6=90 degrees.