Science Questions Please Help Me!! ）

The geographical location is about 62°S, 60°W, and Changcheng Station is located in the West 4th District.

Calculation method: Take the British Gneywich 0 degree longitude. 15 degrees to the east and west is 1 time zone.

The east of the 0 degree meridian is the east longitude, and the west is the west longitude. 60°w is 60 degrees west longitude, so it's 15° 4 = 60°w, so it's 15 degrees in each time zone.

Because at 60°W

The first question is the West Fourth District.

Question 2. 20°W, 35°S in the Southern Hemisphere, and Western Hemisphere.

If you look at 35°S, you're in the Southern Hemisphere, and if it's 35°N, you're in the Northern Hemisphere.

20°W and 160°E are the dividing lines between the eastern and western hemispheres.

After 20°W, the Eastern Hemisphere is reached.

For example, the degree w is the Eastern Hemisphere. But it's still the west longitude.

Do you understand.

In fact, the principle is simple, just some calculations.

The 360-degree Earth is divided into 24 time zones, so each zone is 15 degrees. London is located in the middle of the middle time zone, which is 0 degrees. Left and right are west longitude, east longitude, and the area sandwiched in the middle is exactly 15 degrees, called the middle time zone.

Then add another 15 degrees to the east for the East 1 zone, which is the East Degree-East Degree. In this way, the first question is East 4 District.

Then the second question is the Southwest Hemisphere.

Here's how it goes: W for West, S for South, E for East, N for North. In fact, it is the first letter of the word in the English direction. It comes out at a glance, and you don't have to count it.

Great Wall Station is located in West 4th District: 60°W 15=4

20°W is the dividing line between the eastern and western hemispheres, and 35°s is in the southern hemisphere.

Categories: Life.

Problem description: It takes 12 hours for a steamer to travel from port A to port B, and 13 hours for a steamer to travel from port B to port A. The two steamers sailed opposite each other from the two ports at the same time, and after a few hours the two ships met.

Analytic Tubato: Equation, let the time be x

1/12x+1/13x=1

Just solve it.

23(1) Let the analytic formula of the quadratic function be y=ax +bx+c(a≠0) and the image is a(6,0)b(0,4) and the axis of symmetry is the straight line x=7 2 0=a*6 +6b+c

4=c-b/2a=7/2

The solution is: a=2 3 b=-14 3 c=4 y=2 3x -14 3x+4

2) Let the parabola intersect the x-axis at two points, one point is a(6,0) and the other point is c

Let the abscissa of c be k (k+6) 2=7 2 k=1 i.e.: c(1,0).

1＜xe＜6

e on a parabola.

e(x,2 3x -14 3x+4) e in the fourth quadrant, ye 0 i.e., oh= ye -2 3x +14 3x-4xe 0 i.e., he=|xe|=x

OEH is similar to OAB ob=4, oA=6 and AOB= EHO=90°

If oeh bao

Then: he oa=oh ob

i.e.: x 6=(-2 3x +14 3x-4) 4-12 3x +84 3x-24=4x

x²+6x-6=0

a=-1 b=6 c=-6

b -4ac=6 -4(-1)(-6)=12, so the original equation has two unequal real roots.

x=(-b b -4ac) 2a=3 3

e1（3+√3，-（6+2√3）/3）

e2（3-√3，（2√3-6）/3）

oeh∽△abo

oh/ao=he/ob

-2/3x²+14/3x-4）/6=x/4-8/3 x²+56/3 x-16=6x

8x²+38x-48=0

a=-8 b=38 c=-48

b -4ac=38 -4(-8)(-48)=-92 0 The original equation has no real solution.

If it doesn't fit the topic, give it away.

In summary, the coordinates of the point e are e1(3+ 3,-(6+2 3) 3)e2(3- 3,(2 3-6) 3).

The first one measures out the diameter d and the circumference c= d

The second one is to put 10 drops of water into the graduated cylinder and divide the number by 10

The third is to meet the external conditions for seed germination: 1. Sufficient air, 2. Appropriate temperature, 3. Appropriate amount of water The seed placed on the table does not have the right amount of water.

The first. Measure the diameter d

Circumference c= d

The second. Drop 10 drops of water into a graduated cylinder.

Divide the read number by 10

The third. Meet the external conditions for seed germination.

1. Plenty of air.

2. Suitable temperature.

3. Appropriate amount of water.

The seed that was placed on the table did not have the right amount of water.

1) Solution: If B has worked for x days, then A has worked for x to 5 days. According to the title, A does it alone for 40 days to complete, that is, A does 1 40 per day.

B does it alone for 60 days to complete, that is, B does 1 60 per day. Then, x 60 + (x-5) 40 = 1, and the solution is x = 27. (2) Solution:

Set up team A to work for x days, and team B to work for 10-x days according to the title. Team A chiseled alone for 8 days, that is, A does 1 8 per day, and Team B chisels alone for 12 days, that is, Team B does 1 12 per day. Then x 8 + (10-x) 12 = 1, the solution is x = 4, that is, team A works for 4 days, and team B works for 6 days.

3) Solution: Set to buy apples x kilograms, according to the topic of pears 75-x kilograms. When one-third of the apples are eaten, which is two-thirds of the apples left, and one-fifth of the pears are eaten, which is four-fifths of the pears left, the total amount left is 52 kg, then 2x 3+4(75-x) 5=52.

The solution is x=60, that is, 60 kg of apples and 15 kg of pears are bought. (4) Solution: Set the slow train to stay for x hours.

According to the title, it takes 20 hours to complete the full journey, which is the speed of the express train 1 20. It takes 30 hours to complete the journey, which is 1 30 at the speed of the slow train. Relative departure, 15 hours later, and the express train stayed for 4 hours, that is, the actual travel for 11 hours, the express train traveled 11 20.

If the slow train stays for x hours, i.e. it actually travels for 15-x hours, then the distance traveled by the slow train is (15-x) 30. When they meet, the distance traveled by the two cars is exactly the distance between A and B, so 11 20+(15-x) 30=1, and the solution is x=. So the slow train stays for hours.

The additive solution and the cd additive solution are exactly the same, which is the breakthrough of this problem.

2.The composition of the CD solution can be understood as: original solution = partially saturated solution + (water; Similarly, the composition of the AB solution can be understood as: original solution = later saturated solution - (?) solutes of mg;

3.The last step, depending on the solution being aliquoted, gets: (water + (?) The solute of mg is a saturated solution.

After the above analysis, it can be known that the solubility is Ag

a/100=1/(?)

a=1/(?)100.

The question mark is on behalf of the dissolved quality added in B.,I always feel that the question is missing a little condition.,I've tried my best.,I hope it can help the landlord.。

Point of view: Illegal construction led to the fire.

Evidence: The insulation material did not move away from the fire source after entering the site.

C Contact: After entering the site, the insulation material is burned after encountering sparks in a high-temperature environment.

Hypothesis: Sparks ignite a flammable substance during welding.

I'm a layman, I stumbled across this question and speculated wildly from a layman's eye:

Point of view: The insulation material is not completely covered when it is maintained, and the high-temperature molten iron catches fire when welded

Evidence: In the insulation, welding spatter (molten iron?) was found. Tin? ) residues. __

c Contact: The combustibles on site are limited, and the flammable materials are only insulation materials. There are only workers on the site, if the intention of the workers to set fire is excluded, and there is no cause of fire caused by smoking, it can be determined that there is no cause of fire, polyurethane and other insulation materials can not spontaneously combust, the high temperature source is at the welding place, if the insulation material is used or the material is completely covered, even if there is a high-temperature molten iron splashed past, the combustible polyurethane is isolated from oxygen, and it is impossible to catch fire

S assumption: The insulation material is stacked too close to the operation point, and the coverage is not tight, and when the workers are welding, there is a high-temperature molten (iron?) Splashed into the pile of insulation materials, the workers finished the operation, did not notice the insulation materials that were changing in the pile of materials next to them, after the workers left, the insulation materials reached the ignition point locally, and fully contacted with oxygen, resulting in an open flame and causing a fire.

P: Workers operate in violation of regulations, caused by sparks during welding.

e: The person in charge of the project said.

R: Caused by sparks igniting a flammable substance.

C: The construction operation does not meet the regulations, which is undoubtedly the fuse of the fire.

S: Fires are flammable products ignited by sparks.

Point of view:

Evidence:

c Contact:

Hypothesis:

Workers operate in violation of regulations, and sparks are caused by welding time.

The person in charge of the project said.

Caused by sparks igniting a flammable substance.

The construction operation does not comply with the regulations, which is undoubtedly the fuse of the fire.

Fires are flammable products ignited by sparks.

Humans are differentiated according to gender, age, and ethnicity, and the smallest unit of biological composition is the cell, and eukaryotes are because they have a nucleus in the true sense.