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Anonymous
Anonymous asked in Science & MathematicsMathematics · 1 month ago

7th Grade Math Question?

The ratios of the weights of two objects on the Moon and on Earth are in proportion. A rock weighing 3 N on the Moon weighs 18 N on Earth. How much would a rock that weighs 5 N on the Moon weigh on Earth?

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  • sepia
    Lv 7
    1 month ago

    The ratios of the weights of two objects on the Moon and on Earth are in proportion. 

    A rock weighing 3 N on the Moon weighs 18 N on Earth. 

    A rock that weighs 5 N on the Moon would weigh 30 N on Earth.

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  • 1 month ago

    I won't do your homework for you

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  • Anonymous
    1 month ago

    You have to be at least 13 to be on this site, kid.

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  • Philip
    Lv 6
    1 month ago

    A rock weighing x on the moon weighs 6x on earth. Therefore a rock that

    weighs 5 N n the moon weighs 6(5 N) on earth, ie., 30 N on earth. 

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  • 1 month ago

    Intuitively, we are shown an example where a 3 N object in the moon weighs *6* times as much on the Earth (18 N).

    So clearly a 5 N object on the moon would weigh 30 N on Earth. 

    Here it's very easy to figure out the constant of proportionally in your head. But if you wanted to be a little more mathematically formal, you would solve it as follows:

    Write an equation for the direct variation:

    e = km

    e : weight on Earth (in Newtons)

    m : weight on the Moon (in Newtons)

    k : constant of proportionally

    Plug in what you know about the first object:

    18 = 3k

    Solve for k:

    k = 18/3

    k = 6

    So now you have an equation you can use for other objects:

    e = 6m

    Now when you are told an item weighs 5 N on the moon, you can figure its weight on Earth:

    e = 6*5

    e = 30

    Answer:

    30 N

    Got it?

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  • 1 month ago

    E ∝ M, so E = kM

    Now, when E = 18, M = 3

    so, 18 = 3k

    i.e. k = 6

    => E = 6M

    Hence, when M = 5, E = 30

    i.e. 5 Newtons on the moon will be 30 Newtons on earth.

    Note: This is true as the force due to gravity on the Earth compared to the moon is 6 : 1

    :)>

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  • 1 month ago

    A newton is how much force is required to make a mass of one kilogram 

    accelerate at a rate of one meter per second squared.

    The ratios of the weights of two objects on the Moon and on Earth are in proportion. 

    A rock weighing 3 N on the Moon weighs 18 N on Earth. 

    A rock that weighs 5 N on the Moon would weigh 30 N on Earth.

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  • ted s
    Lv 7
    1 month ago

    18 : 3 as x : 5

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  • alex
    Lv 7
    1 month ago

    5 x 6 = 30N     

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