How many tons of washed sand is used in one cubic meter of casting?

How many tons of washed sand is used in one cubic meter of casting?

More compact about 1.7 tons, and particle size distribution. You can find a large number of cup test!

A classmate used a glass, water and balance to measure the density of a stone. He filled the glass with water and weighed the total mass of the stone to be 200g. After putting in the stone and spilling part of the water, he weighed the total mass to be 215g. Taking the stone out of the glass, he weighed the mass of the water and the glass to be 190g and calculated the density of the stone. (ρ water = 1 × 103kg / m3)

(1) Mass of overflow water: m row = M1-M3 = 200g-190g = 10g, (2) volume of stone: v = V row = m row ρ water = 10g1g / cm3 = 10cm3, (3) mass of stone: M = M2-M3 = 215g-190g = 25g, (4) density of stone: ρ stone = MV = 25g 10cm3 = 2.5g/cm3 = 2.5 × 103 & nbsp; kg / m3

Zero form of cubic function f (x) = x ^ 3 - (a + 1) x ^ 2 + (A-2) x + 2A?)
As above

f(x)=x³+x²-(a+2)x²-(a+2)x+2ax+2a
=x²(x+1)-(a+2)x(x+1)+2a(x+1)
=(x+1)[x²-(a+2)x+2a]
=(x+1)(x-a)(x-2)
So zero is - 1, a, 2

Fill in the blanks 3, - 2,7,11,60, ()

3,-2,7,11,60,（181）

The sum of two natural numbers is 50, and their greatest common divisor is 5
The sum of two natural numbers is 50. When their greatest common divisor is 5, what is the difference between the two numbers,
How many divisors do the two largest odd numbers have? What is the sum of all the divisors,
The sum of the greatest common divisor and the least common multiple of two composite numbers is 143. What are the formulas of these two composite numbers,
A number is divided by 2 to 1, by 3 to 2, by 4 to 3 What is the minimum number of 9 divided by 10,
All arithmetic, no equations. Thank you

1) No matter the method, first determine that two numbers are odd, otherwise the common divisor must be even, and then enumerate (5,45); (15,35), both compound condition 2) the largest two odd numbers are 99, the divisors are 1,3,9,11,33,99, a total of 6, and 1563) first, two numbers are odd and even, so that the largest common divisor

Is there a formula for calculating the static friction of an object on an inclined plane
How did you get it

Yes
Fstatic = mgsina (M is the mass of the object, a is the inclined angle of the inclined plane), and the direction is upward along the inclined plane
According to the equilibrium condition of the body, fstatic = - the component force of gravity in the direction of the inclined plane
Just use it

7 seconds = minutes = hours

73 / 60, 7 / 600

The sum of two prime numbers is even___ ．

Because the smallest prime number is 2, even + odd = odd, all prime numbers except 2 are odd, and the sum of 2 plus any other prime number is odd, it is wrong to say that the sum of two prime numbers is even

On a simple problem of opening cubic root
If we open the complex number a + bi to the third power, that is, to the third power, can we get the analytic solution in the form of C + di? C and D can be expressed as functions of a and B. how can we get it?
If the analytical solution is not available, how to calculate it?

Let (c + DI) ^ 3 = a + B by undetermined coefficient method, then according to the correspondence equality of the imaginary part of the real part, a set of equations can be listed, and the equation about C can be obtained by eliminating D: (C ^ 3-A) * (8 * C ^ 3 + a) ^ 2 = 27 * B ^ 2 * C ^ 3, and let x = C ^ 3, the univariate cubic equation 64 * x ^ 3-48 * a * x ^ 2 - (15 * a ^ 2 + 27 * B ^ 2) * x-a ^ 3 = 0 can be obtained

The problem of digital reasoning in line test
1.5 8 -4 9 （ ） 30 18 21
A.14 B.17 C.20 D.26
2.2 6 13 24 41 （ ）
A.68 B.54 C.47 D.58
3.-4/9 10/9 4/3 7/9 1/9 ( )
A.7/3 B.10/9 C.8/32 D.9/23
4.8/9 -2/3 1/2 -3/8 ( )
A.9/32 B.5/72 C.8/32 D.9/23
5.6 4 8 9 12 9 ( ) 26 30
A.12 B.16 C.18 D.22

Add the beginning and the end step by step
5+21＝8+18＝-4+30＝9+【17】
Second question
2=1+1
6=2+4
13=4+9
24=8+16
41=16+25
On the left side of the plus sign is the equal ratio sequence with a common ratio of 2, and on the right side is the square sequence of natural numbers
Question 3 - 4 / 9 10 / 9 4 / 3 7 / 9 1 / 9
The first case: add the first three items = add the last three items
In the second case, after sharing,
The molecule is - 4,10,12,7,1, []
The denominator is 9
Second term - first term △ 2 = third term, and so on [] = - 5 / 2
So if you divide the bracket by the denominator, you have, [] = - 5 / 18
Divide the first item by the next = - 4 / 3
So (1 / 9) / [] = - 4 / 3 --] = 9 / 32
Add the beginning and the end step by step
36=6+30
30=4+26
(24)=8+【16】
18=9+9
12 = 12 the left side of the equal sign is an arithmetic sequence with a tolerance of 6