Why is it that electric energy is converted into chemical energy when a battery is charged? Why is it that when a battery is charged, electrical energy is converted into chemical energy, while when a battery is used, chemical energy is converted into electrical energy?

When a battery is charged, it needs to be charged, which will consume electrical energy. Of course, electrical energy is converted into chemical energy,
When the battery is used, the electrical appliances get electric energy from it. Naturally, its chemical energy is converted into electric energy. Otherwise, where will the electric energy come from
The principle of rechargeable battery can be seen as follows:

How to solve X / 600 + Y / 200 = 15
The process of giving a sign x + y = 5000

x. Do you have any requirements, otherwise you can't solve them

Energy conversion of fruit battery
How is the energy transformed in the circuit with lemon as power source?

Chemical energy is converted into electric energy. The pH of lemon is lower than 7, and it is acidic. Some free hydrogen ions can form a dot when it meets a conductor and forms a circular circuit, which makes the bulb emit light

The course and efforts of human beings to find a second living space in the universe
Better not be long, not short

It is estimated to be Mars. Scientists have found a large amount of dry ice in the form of carbon dioxide at the poles of Mars. If it is melted, it can cover the entire surface of Mars. Moreover, comets under the surface of Mars have also been found. However, it is not known how the specific wisdom went to the surface of Mars
Time: never stopped since the 20th century, Mars is only a tentative target

We've learned about density, but we don't know the format, calculation and unit conversion,
It's better to have examples,

1. There is a handicraft named pure metal, with a mass of 100 grams and a volume of 6 cubic centimeters, to judge whether it is made of pure gold
ρ gold = 19.3 × 103kg / m3 = 19.3g/cm3
Method 1: calculate the density
The density of handicraft is ρ = m / v = 100g / 6cm3 = 16.7g/cm3 ＜ 19.3g/cm3
So this handicraft is not made of pure gold
Method 2: quality
Suppose this handicraft is made of pure gold, and the mass of 6cm3 is m = ρ v = 19.3g/cm3 × 6cm3 = 115.8g > 100g, so this handicraft is not made of pure gold
Method 3: calculate the volume
Suppose this handicraft is made of pure gold, the volume of 100g pure gold is v = m / ρ = 100g / 19.3g/cm3 = 5.2cm3 < 6cm3, so this handicraft is not made of pure gold
3. In order to cast metal castings, the wood molder uses 0.6 * 10 ^ 3kg / m ^ 3 wood to make the mold according to the plan. If the mold mass is 1.8kg (solid), the alloy material with the density of 2.7 * 10 ^ 3kg / m ^ 3 is used for casting, the casting mass can be calculated
First, the volume of the die v = m / ρ = 1.8kg / (0.6 × 10 3kg / m3) = 3 × 10 - 3m3
The volume of the casting is equal to that of the die, and the mass of the casting is m = ρ v = 2.7 × 10 3 kg / m3 × 3 × 10 - 3 m3
=8.1kg

-4a^-9b^+12ab

Original = - (4a & # 178; - 12ab + 9b & # 178;)
=-(2a-3b)²

If the total resistance is r, please combine the current and voltage characteristics of the circuit according to Ohm's law and prove that r = r1r2r1 + R2

∵ I = I1 + I2, I = ur ∵ ur = u1r1 + u2r2 and ∵ u = U1 = U2 ∵ 1R = 1r1 + 1r2, i.e. r = r1r2r1 + R2

When the vehicle starts to move with an acceleration of 1 m / S2 from standstill, the displacement of the vehicle in the first 5 seconds is 0 The average speed in the second second is The displacement is__ ．

The displacement of the first five seconds is X5 = 12at52 = 12 × 1 × 25 = 12.5m, the displacement of the second second second is x2 = 12at22 − 12at12 = 12 × 1 × 4 − 12 × 1 × 1 = 1.5m, so the average velocity of the second second second second is. V = x2t = 1.51 = 1.5m/s, so the answer is: 12.5m; 1.5m/s; 1.5m

（x-3）²=
（2x-5）²=
a²+b²=
（a/2-1）²=
（-4x+3y）²=

x-3）²=x²-2×x×3+3²=x²-6x+9
（2x-5）²=(2x)²-2×2x×5+5²=4x²-20x+25
A & # 178; + B & # 178; = this can't be counted any more
（a/2-1）²=(a/2)²-2×a/2×1+1²=a²/4-a+1
（-4x+3y）²=(4x-3y)²=16x²-24xy+9y²

There is a small ball with a mass of 3.0kg at the P end of the light thin rod op with a length of L = 0.5m
After the ball reaches the velocity of V = 6.0m/s at the lowest point, it makes a circular motion in the vertical plane with o point as the center, regardless of the friction and air resistance of the thin rod at O. find (10) the velocity of the ball passing through the highest point, (2) the magnitude and direction of the force on the rod OP when the ball passes through the highest point. (g takes 10m / S ^ 2)

Conservation of mechanical energy: 0.5m36 = mg2l + 0.5mv ^ 2, v = 4m / S
Centripetal force = MV ^ 2 / L = 96n, downward. Mg = 30n, so n = 66n, downward
So the rod is subjected to the upward 66n force of the ball

Why is it that electric energy is converted into chemical energy when a battery is charged? Why is it that when a battery is charged, electrical energy is converted into chemical energy, while when a battery is used, chemical energy is converted into electrical energy?