表14-1a。随高度发生的变化 高度Km a/(m/s) 高度举例 9.83 地球表面的平均高度 8.8 9.80 珠穆朗玛峰 366 9.71 最高的载人气球 400 8.70 航天飞机轨道 35700 0.225 通信卫星 Look at the spacecraft: The acceleration from the gravitational force of Earth at that place is not zero!
Look at the spacecraft: The acceleration from the gravitational force of Earth at that place is not zero!!! 高度/Km 0 8.8 36.6 400 35700
Any assumption in above deduction? The earth is regarded as a mass point at its center As we will prove in Sec14-5, for spherical mass distributions we can regard the object as a point mass concentrated at its center. it is an exact relationship So Eq. (14-5)requires the earth is spherical and that its density depends only on the radial distance from its center
As we will prove in Sec14-5, for spherical mass distributions we can regard the object as a point mass concentrated at its center. It is an exact relationship. Any assumption in above deduction? The Earth is regarded as a mass point at its center. So Eq. (14-5) requires the Earth is spherical and that its density depends only on the radial distance from its center
2. The real Earth differs from our model in three way (a The earth is not uniform: (b) The Earth is approximately an ellipsoid(椭球); flattened at the poles and bulging at the equator (c)The earth is rotating 3 How does spin of the earth affect the measure value g of gravitational acceleration go? Fig 14-7 shows the rotating Earth from an inertial frame positioned in space above the north pole. A crate of mass m rests on a platform scale(台秤)at the equator
2. The real Earth differs from our model in three way (a) The Earth is not uniform； (b) The Earth is approximately an ellipsoid(椭球)； flattened at the poles and bulging at the equator (c) The earth is rotating. 3. How does spin of the Earth affect the measure value g of gravitational acceleration g0? Fig 14-7 shows the rotating Earth from an inertial frame positioned in space above the north pole. A crate of mass m rests on a platform scale(台秤) at the equator