What's the difficulty of landing on the moon? It's better to answer another question: what are the difficulties in landing on the moon?

What's the difficulty of landing on the moon? It's better to answer another question: what are the difficulties in landing on the moon?

In my opinion, first of all, the problem of the lunar module should not be too big. If the rocket thrust is too big, it should not be too small. It should have the space for astronauts to move and the necessities of life
2. The fuel problem of the lunar module, how to return from the moon, is also a problem

Simple calculation of fractional multiplication
2/27*（15*27/28）*2/15
15/21*3/4+10/21*3/4-3/4
*It's a multiple sign

2/27*（15*27/28）*2/15
=(2/27x27/28)x(15x2/15)
=1/14x2
=1/7
15/21*3/4+10/21*3/4-3/4
=3/4x(15/21+10/21-1)
=3/4x4/21
=1/7

The giant spaceship that has crashed on the moon for 100 million years, all countries are competing to land on the moon just to study it. Is there such a thing?

There is this cigar like object, for example, in the photos taken by Apollo, but it's too small to judge whether it's a rock or an artifact, and the short-range video of Apollo 20 published on the Internet can't rule out the possibility of forgery. If you're interested, you can find out through the high-resolution images of the moon taken by other spacecraft, The object of that cigar is a rock;

Where is the teaching plan of fraction multiplication

The teaching goal is to enable students to master the mixed operation of multiplication, addition, multiplication and subtraction. Teaching emphasis 1. Master the order of mixed operation of fractions. Blackboard writing topic: mixed operation of fractions 2. Exploration and understanding (1) show examples (2) after reading the problem, ask students to try (board performance on the blackboard) teacher: which problem should be calculated first

China has made a plan for landing on the moon. If an astronaut wants to explore whether there is a magnetic field on the surface of the moon after landing on the moon, he has a sensitive ammeter and a small coil at hand
A. Put the ammeter directly on the surface of the moon to see whether there is indication to judge whether there is a magnetic field. B. form a closed loop with the ammeter and coil to make the coil move in a certain direction. If the ammeter has no indication, judge whether there is a magnetic field on the surface of the moon. C. form a closed loop with the ammeter and coil to make the coil move in a certain direction. If the ammeter has indication, judge whether there is a magnetic field on the surface of the moon If there is a magnetic field on the surface of the moon, the ammeter will not show zero at least once

A. The ammeter and coil are directly placed on the surface of the moon to form a closed loop. Because the coil does not move, the magnetic flux passing through the coil does not change, so the induced current will not be generated, and the pointer of the ammeter does not deflect, so it is impossible to judge whether there is a magnetic field on the surface of the moon, so a is wrong, There is no induced current in the coil, so the ammeter has no indication, so it can't judge that there is no magnetic field on the lunar surface. So B is wrong. C. form a closed loop with the ammeter and coil to make the coil move in a certain direction. If the ammeter has indication, the magnetic flux in the coil changes, indicating that there is a magnetic field on the lunar surface. So C is correct. D. form a closed loop with the ammeter and coil to make the coil move separately If there is a magnetic field on the surface of the moon, the magnetic flux passing through the coil plane will change in one direction. If there is no induced current in both directions, it means that there is no magnetic field on the surface of the moon

Exercises of fractional multiplication

1.4/7×1/7÷4/7×1/7
2.12×(3/4-1/6)
3.12×(1/6+1/2)
4.70×1/35+40×1/35
5.4/5×8×10
6.6×(1/2+1/3)
7.(5/6-2/3)×7/9
8.(1/12+1/5)×60
9.20×(1-1/4-1/5)
10.1/3×7+2/3×7
11.3/4×99+3/4
12.2/7×3/4×14
13.8/9×27+1/9×27
14.2/5×2/7×5/8
15.1/4×8÷1/4×8
16.20×(1/5+1/4)
17.(1/2-1/4)×12
18.5/4×3.6×8
19.(1/8+1/4)×16
20.2/5-2/5×5/12
21.(1/8+1/24)×96
22.17/4×101-17/4
23.28×(4-8/7)
24.(2/3-4/7)×21
25.56×(1/7-1/8)

Which astronaut dreamed of Armstrong as a child?

Yes

Give me the math problems of the fifth grade in the next semester

In the second semester of the fifth grade, oral and direct math problems:
17×40＝ 100－63＝ 3.2＋1.68＝ 2.8×0.4＝
14－7.4＝ 1.92÷0.04＝ 0.32×500＝ 0.65＋4.35＝
10－5.4＝ 4÷20＝ 3.5×200＝ 1.5－0.06＝
0.75÷15＝ 0.4×0.8＝ 4×0.25＝ 0.36＋1.54＝
1.01×99＝ 420÷35＝ 25×12＝ 135÷0.5＝
3/4 + 1/4 = 2 + 4/9 = 3 - 2/3 = 3/4 - 1/2=
1/6 + 1/2 -1/6 = 7.5-(2.5+3.8)= 7/8 + 3/8 =
3/10 +1/5 = 4/5 - 7/10 = 2 - 1/6 -1/3 =
0.51÷17＝ 32.8＋19＝ 5.2÷1.3＝ 1.6×0.4＝
4.9×0.7＝ 1÷5＝ 6÷12＝ 0.87－0.49＝

However, in July 1969, American astronauts Armstrong, Collins and Alder
Lin finally visited the moon on behalf of all mankind, taking an important step in human space exploration and setting up a new milestone in the aerospace industry
② "Saturn 5" makes a rumbling sound, the earth shakes violently, and the rocket rises slowly
③ Apollo 11 has an altitude of 2650 kilometers and a speed of 7.67 kilometers per second
④ In July 1969, the planet of the solar system - human beings on earth left their footprints on the moon for the first time. On behalf of all mankind, we came here for a peaceful journey

1. Narration 2. Description 3. Explanation 4. Discussion

The staircase of a three story office building with veranda is 4.2 meters in width, 6.6 meters in depth and 3.6 meters in height
Mark the staircase floor plan of the staircase; mark the width, length, width and number of steps of the staircase; mark the wall thickness of the staircase 240mm;