Why don't the stars fall
Stars are stars that are far away from us and have little effect on our earth. If the moon can't fall down, it's because the centrifugal force of the Earth Moon system is in balance with the gravity between the earth and the moon, so it won't fall down. This is also the reason why celestial bodies won't collide or fall down
RELATED INFORMATIONS
- 1. Known arithmetic sequence 1,8,15,22 Finding the sum of A6 and A8
- 2. One is that the second term of the arithmetic sequence is 2.8, and the third term is 3.1. Find the 15th term of the arithmetic sequence
- 3. The first term of an arithmetic sequence is 1.2, and the eighth term is 9.6. Find its tenth term
- 4. 1. In the arithmetic sequence {an}, the fourth term is 10 and the eighth term is 22, find its tenth term 2. The third and fourth terms of an equal ratio sequence are 12 and 18 respectively. Find the first and second terms of it
- 5. Sequence (10 18:35:56) Let the sequence {an} satisfy A1 = 9, an + 1 = - 1 / 2An + 3, find the general term formula of an (including process)
- 6. Mathematical sequence problems in grade one of senior high school In the sequence an BN, A1 = B1 = 1, an + 1 = an / 2An + 1, BN + 1-bn = 1 / an, Sn = 1 / B1 + 1 / B2 + 1 / B3 +. + 1 / BN 1. Find BN 2. It is proved that SN is less than nine fourths
- 7. Sequence (15 22:41:41) In the known sequence an, A1 = 160; - 1, a (n + 1) * an = a (n + 1) - an, it is proved that the sequence 1 / an is an arithmetic sequence, and the general term formula of an is obtained
- 8. Given that the arithmetic sequence {an} satisfies an + 1 = an & # 178; - Nan + 1, then an=______ .
- 9. The first n terms and Sn = - n Λ 2 + 9N + 2 (n belongs to n *) of sequence an are known Judge whether it is arithmetic sequence or not
- 10. For example, the general term formula of 6 10 14 18 22 26 and the general term formula of 1 49 16 25 36
- 11. As shown in the figure, it is known that ∠ AOB = 90 °, EOF = 60 °, OE bisects ∠ AOB, of bisects ∠ BOC, and the degrees of ∠ AOC and ∠ cob are calculated
- 12. As shown in the figure, fold a pair of triangular plates together so that the vertices of the right angle coincide with point O, then ∠ AOC + ∠ DOB=______ Degree
- 13. The first pattern needs 7 pieces, the second pattern needs 19 pieces, and the third pattern needs 37 pieces, According to this method, the total number of pieces needed to place the nth pattern is () {hint, the fourth pattern needs 61 pieces; the fifth yuan needs 91 pieces}
- 14. Any parallelogram can be divided into two identical trapezoids______ (judge right or wrong)
- 15. The increasing interval of the function y = - (x-3) multiplied by the absolute value of X
- 16. The probability density of random variable ξ obeying Laplacian distribution is φ (x) = AE ^ f (x) = Ke ^ - | x | and the coefficient a is obtained,
- 17. A supermarket plans to invest a sum of money to purchase a batch of tight selling goods. After market research, it is found that if it is sold at the beginning of this month, it will make a profit of 10%, and then it will invest the capital and profit into other goods, and it will make a profit of 10% at the beginning of next month. If it is sold next month, it will make a profit of 25%, but it will have to pay 8000 yuan for storage?
- 18. XX + yy-2x-2y + 3 proves that no matter how many values XY takes, the answer is not positive
- 19. How to calculate 25 times 125 times 32 with a simple algorithm
- 20. Xiao Ming finds it troublesome to use the formula in the book to calculate the variance of a group of data. Xiao Ming, who is good at using his brain, finds it Xiao Ming finds it troublesome to use the formula in the book to calculate the variance of a group of data. He is good at using his brain to find the simplified formula s ^ 2 = 1 / n [(x1 ^ 2 + x2 ^ 2 +...) +When n = 3, the formula of transformation is s ^ 2 = 1 / n [(x'1 ^ 2 + X'1 ^ 2 +...] +Nx'n ^ 2) - NX '^ 2], where x'1 = x1-a, X'2 = x2-a, X'n = xn-a, is his idea correct? If correct, please prove.