Question about satellite motion?

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Homework Help Overview

The discussion revolves around the motion of satellites, specifically comparing the speeds and altitudes of two satellites, X and Y, as observed from the ground. The original poster expresses frustration over not being able to verify their reasoning regarding the relationship between gravitational attraction and satellite speed.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the relationship between gravitational force and satellite motion, questioning the original poster's reasoning about why one satellite moves faster than the other. They prompt the formulation of equations related to force and acceleration for satellites in orbit.

Discussion Status

Participants are actively engaging with the problem, providing guidance on how to approach the equations governing satellite motion. There is a focus on deriving relevant equations and understanding the implications of gravitational forces on satellite speeds.

Contextual Notes

The original poster's question is based on a textbook problem that lacks an answer, which adds to the complexity of verifying their thought process. The discussion includes assumptions about gravitational effects and orbital mechanics.

Tangeton
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This is one of the questions in the book without an answer and it is really frustrating that I can't check if my through process is correct.

Two satellites X and Y are seen from the ground crossing the night sky at the same time. Satellite X crosses the sky faster than Y. State with a reason which satellite is higher.

I wrote: Satellite Y as the gravitational attraction doesn't act as much on it so it moves around the Earth slower than X does.

Is my answer correct?
 
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Half right. Can you write down an equation for the force and resulting acceleration of a satellite at radius R?
 
haruspex said:
Half right. Can you write down an equation for the force and resulting acceleration of a satellite at radius R?

a= v^2/r and F = mv^2/r , where r is the distance from centre of the Earth to the satellite. Where do I go from here?
 
Tangeton said:
F = mv^2/r , where r is the distance from centre of the Earth to the satellite.
Since it is in orbit, what else is F equal to?
 

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