| Mm |
| (R+h)2 |
| 4π2 |
| T2 |
得：M=
| 4π2(R+h)3 |
| GT2 |
（2）假设月球表面附件有一物体m1，其所受万有引力等于重力
G
| Mm1 |
| R2 |
得g月＝
| 4π2(R+h)3 |
| R2T2 |
（3）根据密度的定义ρ＝
| M |
| V |
月球的体积V＝
| 4 |
| 3 |
所以ρ＝
| ||
|
| 3π(R+h)3 |
| GT2R3 |
答：（1）月球的质量M为
| 4π2(R+h)3 |
| GT2 |
（2）月球表面的重力加速度g月为
| 4π2(R+h)3 |
| R2T2 |
（3）月球的密度ρ为
| 3π(R+h)3 |
| GT2R3 |
| 4 |
| 3 |
| Mm |
| (R+h)2 |
| 4π2 |
| T2 |
| 4π2(R+h)3 |
| GT2 |
| Mm1 |
| R2 |
| 4π2(R+h)3 |
| R2T2 |
| M |
| V |
| 4 |
| 3 |
| ||
|
| 3π(R+h)3 |
| GT2R3 |
| 4π2(R+h)3 |
| GT2 |
| 4π2(R+h)3 |
| R2T2 |
| 3π(R+h)3 |
| GT2R3 |