Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    0
    ReputationRep:
    Help with the gravitation question please

    Name:  Untitled.jpg
Views: 73
Size:  12.1 KB
    • Community Assistant
    Offline

    19
    ReputationRep:
    The gravitational field strength is proportional to the product of density and radius. Does this help?

    Spoiler:
    Show
    This is because g=\frac{GM}{r^2} and M=DV and V=\frac{4 \pi r^3}{3}
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Mr M)
    The gravitational field strength is proportional to the product of density and radius. Does this help?

    Spoiler:
    Show
    This is because g=\frac{GM}{r^2} and M=DV and V=\frac{4 \pi r^3}{3}
    thanks that was a bit helpful
    • Community Assistant
    Offline

    19
    ReputationRep:
    (Original post by Beamchain)
    thanks that was a bit helpful
    Just a bit?!
    Offline

    3
    ReputationRep:
    1st calculate the volume (1.6x10^7)^3 x 4pi/3 = 1.715x10^22
    now times by 3000 to get mass = 5.14x10^24
    g=((6.67x10^-11)x(5.14x10^24))/((1.6x10^7)^2) = 13.4N/kg
    • Community Assistant
    Offline

    19
    ReputationRep:
    (Original post by shahbaz)
    1st calculate the volume (1.6x10^7)^3 x 4pi/3 = 1.715x10^22
    now times by 3000 to get mass = 5.14x10^24
    g=((6.67x10^-11)x(5.14x10^24))/((1.6x10^7)^2) = 13.4N/kg
    It isn't necessary to make any calculations to obtain the correct answer.
    Offline

    3
    ReputationRep:
    (Original post by Mr M)
    It isn't necessary to make any calculations to obtain the correct answer.
    Why not?
    • Community Assistant
    Offline

    19
    ReputationRep:
    (Original post by shahbaz)
    Why not?
    Because the product of density and radius is the same for both planets.
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Did TEF Bronze Award affect your UCAS choices?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Quick reply
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.