Satellite Motion: Speed & Period Video Lessons

Concept

# Problem: Two satellites orbit the Earth in circular orbits of the same radius. One satellite is twice as massive as the other. Which statement is true about the speeds of these satellites? (a) The heavier satellite moves twice as fast as the lighter one.(b) The two satellites have the same speed. (c) The lighter satellite moves twice as fast as the heavier one. (d) The ratio of their speeds depends on the orbital radius.

###### FREE Expert Solution

Satellite orbital speed:

$\overline{){\mathbf{v}}{\mathbf{=}}\sqrt{\frac{\mathbf{G}{\mathbf{m}}_{\mathbf{e}}}{\mathbf{r}}}}$

me is the mass of the earth and r is the radius.

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###### Problem Details

Two satellites orbit the Earth in circular orbits of the same radius. One satellite is twice as massive as the other. Which statement is true about the speeds of these satellites?

(a) The heavier satellite moves twice as fast as the lighter one.

(b) The two satellites have the same speed.

(c) The lighter satellite moves twice as fast as the heavier one.

(d) The ratio of their speeds depends on the orbital radius.