Section 3.2 and 3.3 in Matter and Interactions (4th edition)
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===== Gravitational Acceleration =====
===== Gravitational Acceleration =====
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→a2=−Gm1|→r|2ˆr
→a2=−Gm1|→r|2ˆr
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The resulting expression is the acceleration that object 2 experiences due to it's gravitational interaction with object 1. Notice that the acceleration of object 2 depends only on the mass of object 1 (m1), and relative position of object 2 with respect to object 1 (→r). It also points towards object 1, which indicates that the object 2 is attracted (and will thus experience an acceleration along the line between object 1 and 2).
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//__The resulting expression is the acceleration that object 2 experiences due to it's gravitational interaction with object 1__//. Notice that the acceleration of object 2 depends only on the mass of object 1 (m1), and relative position of object 2 with respect to object 1 (→r). It also points towards object 1, which indicates that the object 2 is attracted (and will thus experience an acceleration along the line between object 1 and 2).
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So, in general:
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So, __in general__:
→a=−Gm|→r|2ˆr
→a=−Gm|→r|2ˆr
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For simplicity, let's take the downward vertical direction to be positive. Let's compute the acceleration due gravity at the surface of the Earth. Here the [[http://lmgtfy.com/?q=mass+of+the+earth|mass of the Earth]] is roughly 5.97×1024kg and [[http://lmgtfy.com/?q=radius+of+the+earth|the radius of the Earth]] is 6.38×106m.
For simplicity, let's take the downward vertical direction to be positive. Let's compute the acceleration due gravity at the surface of the Earth. Here the [[http://lmgtfy.com/?q=mass+of+the+earth|mass of the Earth]] is roughly 5.97×1024kg and [[http://lmgtfy.com/?q=radius+of+the+earth|the radius of the Earth]] is 6.38×106m.
which is pretty close to the value we often use. In fact, the gravitational acceleration fluctuates a few percent over the surface of the Earth due to [[http://en.wikipedia.org/wiki/Gravity_anomaly|gravitaitonal anomalies]]. The variations in the Earth's crust that are primarily responsible for these anomalies were mapped by the [[http://en.wikipedia.org/wiki/Gravity_Recovery_and_Climate_Experiment|GRACE Experiment]].
which is pretty close to the value we often use. In fact, the gravitational acceleration fluctuates a few percent over the surface of the Earth due to [[http://en.wikipedia.org/wiki/Gravity_anomaly|gravitaitonal anomalies]]. The variations in the Earth's crust that are primarily responsible for these anomalies were mapped by the [[http://en.wikipedia.org/wiki/Gravity_Recovery_and_Climate_Experiment|GRACE Experiment]].