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在教材“万有引力与航天”一章中我们经常需要利用一些常量,如万有引力常量G=6.67×10-11N·m2/kg2,地球表面重力加速度g=9.8m/s2,第一宇宙速度v=7.9km/s,地球的自转周期24小时,地球的公转周期365天,月球的公转周期27.3天等.这些常量中除了月球公转周期之外的其它常量大家都非常熟悉.由于月相变化周期为29.5天,即我们的农历月的时间(农历月29天与30天交替,平均29.5天),为什么月球绕地球公转周期是27.3天呢?二者为什么不等呢?二者之间到底存在什么样的联系呢?
We often need to use some constants such as gravitational constant G = 6.67 × 10-11N · m2 / kg2 and g = 9.8m / s2 on the earth’s surface in the textbook “Gravitation and Aerospace”. The first cosmic velocity v = 7.9km / s, the earth’s rotation period of 24 hours, the earth’s revolution period of 365 days, the moon’s revolution period of 27.3 days, etc .. In addition to these constants in addition to the lunar revolution period of the other constants are very familiar with the moon phase change cycle Is 29.5 days, that is, the time of our Lunar New Year (29 and 30 days lunar lunar month, an average of 29.5 days), why the lunar orbit around the Earth cycle is 27.3 days? Why both do not exist? Between the two exist What kind of contact?