Planet and speff problem find mass

  • #1

Homework Statement


The weigh tof spaceman speff, soley due to the gravitational pull of planet x at its surface is 389N. If he moves to a distance of 1.86*10^4km above the planets surface his weight changes to 24.31N. What is the mass of planet xif speffs mass is 75 kg.


Homework Equations



f=ma
f=gm1+m2/r^2

The Attempt at a Solution


i know the answers is 2.96*10^24 kg. nut idk how to get it
 

Answers and Replies

  • #2
SteamKing
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I would double check your second equation.
 
  • #4
what else?? im still not getting it
 
  • #5
Redbelly98
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Use the F=G·m1·m2/r2 equation, and plug in the given information. There are two sets of information, so you would get two equations:

(1) 389 N = G · __ · __ / __
(2) Use the other weight given in the problem to set up the second equation
 

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