I m a freshman in my second year of junior high school and I would like to ask you a few questions!!

5. It can hold 50 grams of water. So the volume is 50cm 6, the metal discharges 50 grams of water, and the volume is 50cm. The weight is 500-300=200 grams, so the density is kilogram m

7. There is no figure.

8. From results 1 and 2, the volume of 16 grams of liquid can be obtained is 20cm. The density is gram cm, i.e. 800 kilograms m

Add another 5cm, the weight increases by 4g, m = 38 + 4 = 429, the equipment used: a measuring cylinder larger than a candle, an electronic scale (obviously the measuring cylinder cannot be measured with a balance), sufficient water.

Step: Measure the weight of the graduated cylinder filled with water, denoted a

Place the candle to be measured in the graduated cylinder.

Measure the weight of the graduated cylinder at this time and denote it as B

Remove the candle and measure the weight of the measuring cylinder, denoted as c.

c-a is the weight of the water that flows out, and the volume of the candle can be calculated.

b-c is the weight of the candle.

Dividing the candle weight by the volume gives the candle density.

First of all, the mass of water is gram-gram = 40 grams, and then the volume is equal to the mass divided by the density by the formula, and the density of water is 1 gram per cubic centimeter, and the mass is 40 grams, so the volume is 40 divided by 1 = 40 cubic centimeters.

The mass of water is 50 grams, and the density is 1 gram per cubic centimeter, so the volume of water is 50 cubic centimeters, i.e. the volume of the bottle is 50 cubic centimeters.

The mass of the alloy block is 500-300 = 200 grams, and the volume occupied is the volume of the spilled water. The mass of water is 350-300 = 50 grams, the density is 1 gram per cubic centimeter, and the volume occupied is 50 cubic centimeters. So the density of the alloy block is 200 grams 50 cubic centimeters = 4 grams per cubic centimeter, which is 4000 kilograms m3

7.I can't see the diagram.

42 Let the density of this liquid be p and the mass of the container be m, and the first two sets of data can be columnarized:

15p+m=22

35p+m=38

This density is obtained as grams per cubic centimeter, i.e. 800 kilogram m3; The mass of the container is 10 grams. So m = grams.

9.(1) Ruler, scale.

2) Use a ruler to measure the diameter of the bottom surface of a small section of candle (cylinder) and then obtain the radius to calculate the bottom area; Measure the height with a ruler to obtain v=sh volume. The mass of the candle (cylinder) is measured with a balance. Divide the mass by the volume to get the density of the candle (cylinder).

1.Negative and zero.

2.Original = (1-2) + (3-4) + (5-6) + ....2007-2008）(-1)x2008/2

3.Original = supplemental: 11 days.

1) Negative number 0

2) The first and second terms are -1, and the third and fourth terms are -1, with a total of 1004 items, the result is -1004

3) After removing the brackets, it is 1 2-1 2+1 3-1 3 ......+1 99-1 99+1 99 can be eliminated in front of the end to 1 1000

4) Add 1 to each number and subtract 4 to 90 + 900 + 9000 + 90000-4 = 99990-4 = 99986

3) Disassemble, =1 2-1 2+1 3-1 3+·· 1 100 =1 100

4) +1 = 90+900+9000+90000+90000=99990

Subtract the added 4 1s = 99990-4 = 99986

Machine A produces x parts per hour B y

x=2000

y=850A did=pcs.

B did =8y=6800.

Let A do x and B make y.

4x-4y=4200

Find: x=1840

y=790

The efficiency of the machine is 2000 hours.

B efficiency is 850 hours.

A total of 11,000 pieces were produced.

A total of 6800 pieces were produced.

In the first question, calculate from the outside in, we get a=-2, and the opposite number is 2.

The second question is that you don't say the absolute value, you can't compare.

Since a is on the straight line y=2 3x, then substituting the equation is obtained.

m=2/3 * 6)=-4

So the coordinates of point A are (-6, -4).

And since point A is also on y=k, then k = -4

So the straight line is y=-4

Solution: -6*(2 3)=m from the meaning of the question

That is, m=-4 and because m=k, k=-4

So the coordinates of a are (-6,-4), and the analytic formula is y=-4

point a is on y=2 3x, so x=-6, m=-4

m is the value on the y-axis, and k is a constant.

Hence y=-4

1.A prism has 14 vertices, which means that there are 7 vertices above and below, and there are 7 side edges, each of which is 5 cm long

2.The bottom circumference of this conical surface is:

2*π*r*1/2=10π=2*π*r

r=5s=π*r^2=25π

The 14 vertices are heptagram prisms, each of which is approximately 5 cm long.

1.Solution: It is easy to know that there are 7 prisms with a length of (5) cm on each side

2.According to the circumference of the base circle = the arc length of the side fan, 2 r = 10 r = 5

The base area of this conical surface is (25) square centimeters.

1. (Old judgment 1) (2) (bumper 3) is correct.

2. D3, the right smile with the cover turns 80°

This is a right-angled triangle: the kilometer (the straight long side of the triangle) The kilometer (the straight and short side of the triangle) The kilometer is the hypotenuse of the triangle.

Calculate the prudent length of ba: ba squared = (square + squared.

ba square = square + squared.

ba squared = ba squared =

ba = kilometer.

That's 7/27, 6/27 when there are two, and 1/27 when there are three.

Not so much.

The number of vehicles that appear by pressing "Left, Center, Right" can only be as follows:

The result is a combination, not a permutation, so the order of the three cars does not need to be taken into account.

This seems to be a high school permutation... A total of 8 situations... Four in line with the ...

This is the first year of junior high school question. You scare me.