The unit of steel plate is 1 meter long, 1 meter wide and 2 cm thick, and the weight is calculated

The unit of steel plate is 1 meter long, 1 meter wide and 2 cm thick, and the weight is calculated

The density of ordinary steel plate is 7.85 g / cm3
The theoretical weight of 20 mm thick iron plate per square meter is 157.0 kg. Your plate is 1 × 1 square, which is 157 kg
High alloy steel, stainless steel, etc. can not refer to this standard

There is a rectangle, its length and width increased by 8 cm, the area of this rectangle increased by 208 square cm, the original rectangle circumference is () cm
A. 144B. 36C. 72D. 18

As shown in the figure, (208-8 × 8) △ 8 × 2, = (208-64) △ 8 × 2, = 144 △ 8 × 2, = 36 (CM)

It is known that the image of hyperbola: y = K / X and parabola: the square of y = ax + BX + C (a ≠ 0) intersects with X-axis at M (2,0), n (3,0), intersects with Y-axis at d (0,6), and E is the vertex of parabola
(1) (2) the area of △ dne

Parabola: the image of y = the square of AX + BX + C (a ≠ 0) intersects the x-axis at two points m (2,0), n (3,0), and intersects the y-axis at point d (0,6),
c=6
4a+2b+c=0
9a+3b+c=0
a=1 b=-5 c=6
y=x²-5x+6
E(5/2,-1/4)
Intersection of de two point line and X axis (12 / 5,0)
The area of △ dne = 1 / 2 × 6 × (3-12 / 5) + 1 / 2 × 1 / 4 (3-12 / 5) = 15 / 8

How many tons is a cubic meter, please?
How is this formula converted?
How many tons is a cubic meter of river sand?

Cubic meter is the unit of volume, ton is the unit of mass, two can not be equated. It is related to the density of matter. Density is an attribute of matter (just like volume and mass). For example, the density of water is 1000kg / m ^ 3, so the mass of 1m ^ 3 water is 1000kg, that is, the density of 1 ton kerosene is 800kg / m ^ 3, so

The number of times of the result of the addition and subtraction of an integer () the number of times of each original integer

The number of times of the result of the addition and subtraction of an integer (=) the number of times of each original integer

When ∫ ∫ 1dxdy, the integrand is 1, that is to say, the area is obtained,

If the integrand function is 1, it is indeed the area of the integral interval. If 1 is replaced by X, it is volume. In short, the single integral can be regarded as area, the double integral is volume, and the triple integral is mass. Because the volume of an object with height 1 is the same as that of its bottom area

Advance rate between volume units
Unit and rate (separate)
Volume and volume! (complete)

Volume unit:
Cubic meter (m ^ 3), cubic decimeter (DM ^ 3), cubic centimeter (cm ^ 3), cubic millimeter (mm ^ 3), liter (L, sometimes l), milliliter (ML, sometimes ml)
1m^3＝1000dm^3,1dm^3＝1000cm^3,1cm^3＝1000mm^3,1dm^3＝1L,1cm^3＝1mL,1L＝1000mL.

(a-b-2c) square

(a-b-2c)^2
=[(a-b)^2-2*2c(a-b)+4c^2]
=a^2+b^2-2ab-4c(a-b)+4c^2
=a^2+b^2-2ab-4ac+4bc+4c^2
=a^2+b^2+4c^4-2ab+4bc-4ac

The graph is a part of the parabola y2 = 2px. If the focus of the parabola is exactly on the line x + Y-1 = 0, we can find the parabola
The graph is a part of the parabola y2 = 2px. If the focus of the parabola is exactly on the line x + Y-1 = 0, the parabolic equation can be solved

The focus is (P / 2,0)
In X + Y-1 = 0
p/2+0-1=0
p=2
So y & # 178; = 4x

100 ml 95% solution if the configuration of 75% disinfectant alcohol solution need to add how much ml of water?

The density of 95% alcohol is close to 0.8g/ml. Therefore, the mass of 95% alcohol in 100ml is 80g, the alcohol content is 76g, and 76 / 75% = 101.33g solution is formed with 75% alcohol, so 21.33g water is needed