A question that asks you to figure out the mass of the moon

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Homework Help Overview

The discussion revolves around calculating the mass of the moon using its radius and acceleration due to gravity relative to Earth. Participants are exploring the relationships between these variables and the gravitational constant.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the use of gravitational equations to relate the moon's mass to known values, questioning whether the mass of Earth is necessary for the calculation. Some express concern about memorizing constants for an upcoming exam.

Discussion Status

There is a mix of attempts to set up the problem and clarify the necessary equations. Some participants suggest that knowing the formulas is essential, while others question the need for the mass of Earth in the calculations. The discussion is ongoing with various interpretations being explored.

Contextual Notes

Participants mention constraints related to an exam setting, including the lack of provided equations and constants, which may influence their approach to the problem.

Hmpca
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Homework Statement



the radius of the moon is 1 over 3.65 of the radius of the earth, while the acceleration due to gravity of the moon is 1 over 6 of that on the earth`s surface. calculate the mass of the moon.
 
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Hmpca said:

Homework Statement



the radius of the moon is 1 over 3.65 of the radius of the earth, while the acceleration due to gravity of the moon is 1 over 6 of that on the earth`s surface. calculate the mass of the moon.

The acceleration due to gravity - we call it g on Earth - is given by GM/R2. Where G is the universal constant of gravitation; M is the mass of the central body; and R is the distance form the centre of mass - the radius of the body if we consider g on the surface. You know sufficient of those values to calculate the mass of the Moon as a fraction of the mass of the Earth, which is a value that can be looked up easily.
 
i thought you could figure out the mass of the moon without knowing the mass of the earth. tomorrow i have an exam and my teacher said don`t expect me to give you any sheet with equations and constants. so i guess i got to memorize the mass of the earth.
thank you
 
a = GM/R2

g = (1/6)(9.81) = X m/s2

r = (1/3.65)(6.378x106) = Y m

m/r2 = a/G

m/(Y)2 = X/ (6.67x10-11)

m = ANS kg
 
the person asking for help is supposed to set up the problem, give relevant equations etc. before getting help from outside. Where are your equations??

In answer to your question - you do have to know the formulas probably but not the mass of the earth.
 

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