Keplers laws of motion - quick question on units

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Homework Help Overview

The discussion revolves around the application of Kepler's laws of motion, specifically focusing on the calculation of radius using a given formula. Participants are examining the units involved in the equation and their implications for the final result.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are questioning the units of the gravitational constant and its role in the equation, particularly how it affects the calculation of radius. There is confusion regarding the cancellation of units, especially with the mass term.

Discussion Status

Some participants have provided clarifications regarding the distinction between the gravitational constant (G) and gravitational acceleration (g), which has helped to address the confusion about units. However, there is no explicit consensus on the resolution of the unit issue.

Contextual Notes

Participants are working under the assumption that the formula provided is correct as per class instruction, but they are grappling with the implications of the units involved in the calculation.

channel1
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Homework Statement


find the radius
R3=((T2GM/(4∏2))1/3


The Attempt at a Solution


simple enough, my only question is when I plug in T (units: sec) G (units: m/s^2) and M (units: kg) there is nothing to cancel out the kg so my R is not in units of meters...the equation is correct because we were given it in class but what's going on with the units?
 
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channel1 said:

Homework Statement


find the radius
R3=((T2GM/(4∏2))1/3


The Attempt at a Solution


simple enough, my only question is when I plug in T (units: sec) G (units: m/s^2) and M (units: kg) there is nothing to cancel out the kg so my R is not in units of meters...the equation is correct because we were given it in class but what's going on with the units?

Homework Statement




Homework Equations





The Attempt at a Solution


G in this problem isn't an acceleration. It's the gravitational constant G. The units are m^3/(kg*s^2).
 
channel1 said:

Homework Statement


find the radius
R3=((T2GM/(4∏2))1/3

The Attempt at a Solution


simple enough, my only question is when I plug in T (units: sec) G (units: m/s^2) and M (units: kg) there is nothing to cancel out the kg so my R is not in units of meters...the equation is correct because we were given it in class but what's going on with the units?

Homework Statement


That's G, not g :wink:

EDIT: Beaten to the punch!
 
Ah hah! Thank you both!
 

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