A cylinder with a bottom radius of 5cm and a height of 20cm is cut into two cylinders of the same size. The sum of the volume and the surface area of the two small cylinders is the same as the cross section What's the change of the cylinder?

The volume sum of two small cylinders
3.14*5²*20=1570cm³
The sum of the surface areas is two more sections than the surface area of the cylinder
2*3.14*5²=157cm²

Why can the similar horizontal motion be calculated by the method of horizontal motion? What is its principle
Our teacher hasn't talked about it yet
For example, a particle has a vertical downward initial velocity and a constant horizontal rightward external force,
It can be seen as the particle moving in a straight line with uniform velocity along the x-axis and in a straight line with uniform acceleration with initial velocity 0 along the y-axis
How do you understand that

It's very simple. The core of horizontal throwing motion is the decomposition of velocity, that is, to decompose velocity into horizontal uniform velocity and vertical uniform addition, while similar horizontal throwing (such as "horizontal throwing" on inclined plane) can also be decomposed into two directions of velocity, so as to solve the problem
I hope you understand.

A 20 ohm resistance, connected to 4 dry batteries series power supply, measure the current in the resistance and the voltage at both ends, the range of ammeter and voltmeter is

Because the total voltage is 4 * 1.5 = 6V, and because it is in series, the current is 6 / 20 = 0.3A, so the ammeter selects the small range of 0 ~ 0.3, and because the voltage is 6V, the voltmeter selects the large range of 0 ~ 15

There's a chemical equation for calcium carbonate
Urgent! Thank you!

CaCO3 = = CaO + CO2 ＋ (high temperature) CaCO3 + 2HCl = CaCl2 + H2O + CO2 ＋ 2hno3 + CaCO3 = Ca (NO3) 2 + H2O + CO2 ＋ H2SO4 + CaCO3 = CaSO4 + H2O + CO2 ＋ CO2 + CaCO3 + H2O = Ca (HCO3) 2co2 + Ca (OH) 2 = CaCO3 ↓ + H2O Ca (OH) 2 + Na2CO3 = = = CaCO3 ↓ + 2naoh

When the car goes from place a to place B, it takes 15% of the whole journey first, and then travels 50 kilometers. At this time, the ratio of the distance that has been traveled to the distance that has not been traveled is 2:3. How many kilometers are there between a and B

50 ± [2 ± (2 + 3) - 15%] = 50 ± 25% = 200 km

What is the equation of the straight line where the chord passing through point a (3, negative 1) and bisected by a minus y = 1 from the hyperbola x ratio 4

X ^ 2 / 4-y ^ 2 = 1x ^ 2-4y ^ 2 = 4 if the slope of the line does not exist, then the line is perpendicular to the X axis, that is, x = 3. Because the hyperbola is symmetrical about the X axis, then it is obvious that the midpoint of the intersection of the line and the hyperbola is on the X axis, and a is not on the X axis, so the slope of the line exists. If the slope is k, then y + 1 = K (x-3) y = KX - (3K + 1) is substituted into x ^ 2-4y ^ 2 = 4x ^ 2-4 [K ^ 2x ^ 2-2k

Can three alternating current be changed to two 220 V, and air conditioning be installed

Pull out any one of the three phases, then pull out the zero line, and finally pull out the grounding wire

It is known that f (x) = 1-2a-2acosx-2sin & # 178; X, a ∈ R. when a = 1, the maximum value of F (x) is obtained

f(x)=1-2a-2acosx-2sin²x
=2cos^2x-2cosx-3
=2(cosx-1/2)^2-7/2
x=(2k+1),k=0.1.2.
f(x)max=1

How much electricity does a 180 watt appliance consume per hour?

180W = 0.18kw, 1 kwh = 1kwh (KWH)
0.18kw × 1H = 0.18kwh (degree)
The power consumption is 0.18 degree per hour

D department = the square of E department + the square of E department

This is the content of the University, high school only requires to know the conclusion!

A cylinder with a bottom radius of 5cm and a height of 20cm is cut into two cylinders of the same size. The sum of the volume and the surface area of the two small cylinders is the same as the cross section What's the change of the cylinder?