Does dry battery convert electric energy into chemical energy or chemical energy into electric energy? The answer is that chemical energy is converted into electrical energy. Why? I can't figure it out! I always think that electrical energy is converted into chemical energy

Does dry battery convert electric energy into chemical energy or chemical energy into electric energy? The answer is that chemical energy is converted into electrical energy. Why? I can't figure it out! I always think that electrical energy is converted into chemical energy

If it's like what you said, then the battery is not called a battery. The end result is electric energy, because you need electricity. What you said is rechargeable battery. Charging current affairs, electric energy is converted into chemical energy

1. According to the given equation x times (1 + 20%) * 70% = 4200, please write a practical problem of discount sales and answer the problem you designed
It is understood that the sales of clothing in individual clothing stores can be profitable as long as it is 20% higher than the purchase price, but the owners often price it at 50% - 100% higher than the purchase price. If you are going to buy a garment with a price of 180 yuan, within what scope should you counter-offer to complete the transaction
3. In autumn, the lambs in Yangcun harvest a lot of corn, but in the process of distribution, they find that if each lamb is 50, there will be 40 less, if each lamb is 40 and there are 20 left, then you know how many lambs there are in Yangcun. If these are math problems, please tell me how to write them

1. A product is priced at 20% of the ex factory price, and then sold at a 70% discount. The hourly price is 4200 yuan. What's the ex factory price?
Set ex factory price X Yuan
X times (1 + 20%) * 70% = 4200
x=5000
The ex factory price is 5000 yuan
2. Buy a garment with a price of 180 yuan, which is 50% to 100% higher than the purchase price. The purchase price is 180 (1 + 50%) = 120
And 180 (1 + 100%) = 90 yuan, as long as 90 * (1 + 20%) = 108 and 120 * (1 + 20%) = 144 yuan, you can make a profit
Therefore, in the 90-144 yuan counter-offer
3. There are x sheep
50x-40=40x+20
x=6
There are six lambs in Yangcun

Energy is closely related to life. The following chemical reactions are used to obtain electricity
A. Wind power B. hydropower C. thermal power D. solar power

A. There is no new material generated in the process of wind power generation, which is a physical change, not the use of chemical reaction to obtain electric energy. B. there is no new material generated in the process of hydropower generation, which is a physical change, not the use of chemical reaction to obtain electric energy. C. thermal power generation is the use of coal combustion heat, which is a chemical change

1. As shown in Figure 1, △ ABC, ab = 3, BC = 5, AC = 4, now fold it so that point B coincides with point C, and calculate the length of crease de. [figure 1] 2. As shown in Figure 2, in trapezoidal ABCD, ad ‖ BD, ab = 3, BC = 7, CD = 4, Da = 2, calculate the area of trapezoidal ABCD. [figure 2] 3. As shown in Figure 3, in rectangular paper ABCD, ab = 8, BC = 4, fold the rectangular paper along AC, and point d falls at point d '; calculate the area of overlapping part △ AFC. [figure 3] 4, Given that ab = 5, BC = 3, CD ⊥ AB at point D, and CD = 12 / 5, is △ ABC a right triangle

1、△ABC∽△DEC DE=0.5*BC/AC*AB=0.5*5/4*3=1.875.
2. This problem is wrong. Ad ‖ BD is impossible
3. It can be seen from the question that RT △ BFC ≌ RT △ d'fc means d'f + AF = 8, d'f ^ + 4 ^ = AF ^ so d'f = 3,
S△AFC= S△D'AC- SD'DAF=0.5*4*8-0.5*4*3=10
4. In RT △ BDC, BD ^ = BC ^ - CD ^ D = 9 / 5; in RT △ ADC, AC ^ = ad ^ + CD ^ AC = 4,
Because AB ^ = AC ^ + BC ^, △ ABCA is a right triangle

How many jin is 5 liter peanut oil? Some say 9.2 Jin, some say 9 Jin, some say 10 jin, some say more than 8 Jin. Who can give the correct answer,

Generally speaking, the density of peanut oil is 0.918, that is to say, 0.918kg * 5 = 4.59kg,
The density of peanut oil shall refer to the national standard of peanut oil GB / t1534-2003

It is known that a2-6a + 9 and | B-1 | are opposite numbers, then the value of (AB − BA) / (a + b) is______ ．

From the meaning of the title, we know that a2-6a + 9 + | B-1 | = (A-3) 2 + | B-1 | = 0, | A-3 = 0, B-1 = 0, | a = 3, B = 1

Is the resistance of superconductor really zero
If it is really zero, according to Ohm's law I = u / R, then the denominator of the fraction is not zero?
Is it infinitesimal?

In theory, there should be a small value (less than the lowest resistance we can measure). In the experiment, because of the accuracy of the instrument, we can not get the accurate value, because the resistance caused by other factors is greater than the resistance in the superconducting state
Ohm's law is only an approximate law obtained from experiments, which can't describe the law of superconductivity
PS: Generally speaking, there is divergence in many physical problems (that is, the denominator is zero). For example, the size of the electron has not been measured at present. If we take it as a point, the electric field and density will diverge at this point. By improving the existing theory and solving the divergence problem, we can promote the development of science

After a period of time, a particle moves in a straight line with uniform acceleration and deceleration until it stops. The acceleration is A2 and the displacement of the whole process is X

Let the maximum velocity in the motion process be VM, then the total time t = VMA1 + vma2 & nbsp; & nbsp; ① then the total displacement x = vm2t1 + vm2t2 = vm2t & nbsp; & nbsp; & nbsp; ② simultaneous solution of the two equations gives t = 2 (a1 + A2) xa1a2

For all the formulas from speed to electricity, it's better to explain what each letter stands for. It's better to send the important knowledge points of this formula and some classic topics
I'm going to take the senior high school entrance examination. My formula is not good enough. Please copy it better
OK, you can get extra points
Please translate the formula into Chinese by the way. The layout should be neat, and the space should not be too large, which is convenient for me to recite

Junior high school physics formula, commonly used physics formula and important knowledge point physical quantity unit formula name symbol name symbol mass m kg kg m = ρ V temperature T centigrade ° C velocity v m / S M / S v = s / T density p kg / M 3 kg / m3 ρ = m / V force (gravity) f Newton (cow) n

A long board with mass m = 1kg is still on the horizontal plane
The dynamic friction coefficient between the long board and the horizontal plane is 0.1. A small sliding block with mass m = 2kg slides from the left end of the long board to the long board at the speed of V = 1.2m/s. The dynamic friction coefficient between the sliding block and the long board is 0.2
1. After how many times, the speed of the small slider is the same as that of the long board
2. What is the sliding distance of the small slider relative to the ground during the process of sliding the small slider onto the long board and finally coming to rest (relative to the ground) (the slider never slides away from the long board)

I'm not going to be specific. Let me give you some ideas
When the slider is on the board, it receives the friction force from the board and decelerates evenly. The acceleration can be calculated. If you set the speed equal to V and the time equal to t, you can give a formula
When the board receives the friction from the ground, it is very difficult for the slider to give it the resultant force of friction. The direction is forward, and the acceleration motion is uniform. It is also V and t. another formula can be solved
The second problem, V and T, is solved. You can further formulate and calculate the distance