You have to set the gravitational force equal to the centripetal force to understand the relationship between the two satellites. After all, the gravitational force IS the centripetal force:

Fc = (m_{sat})x(v)^{2/r}

Fg = Gx(m_{earth})x(m_{sat})/r^{2}

Gx(m_{earth})x(m_{sat})/r^{2}= (m_{sat})x(v)^{2/r}

Gx(m_{earth})/r = v^{2}

v = square root (Gx(m_{earth})/r)

This equation shows you that the smaller the r, the greater the v.

## In Physics Module 8 test question 8, if centripetal force depends on the inverse of r, why is the closer satellite the one that moves faster?

- Last update:
- 2017-11-20 19:06
- Author:
- Sue
- Revision:
- 1.1

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