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What do we mean when we say 1 kg of bananas ?

  1. Dec 28, 2012 #1
    What do we mean when we say "1 kg of bananas"?

    1. The problem statement, all variables and given/known data
    If I buy 1 kg bananas in a supermarket on the moon, will I get the same amount (mass) of bananas as if I bought them on the earth?

    2. Relevant equations

    w=mg
    g moon = 1/6 g earth

    3. The attempt at a solution
    It depends on what they mean by 1 kg surely. If the supermarkets are meaning 1 kg mass, the answer is yes. If they mean 1 kg wt (= force) then no. What does the supermarket mean when they say "1 kg"?

    Another way of looking at it: If they us an oscillatory balance, yes. But, if they use a spring balance, no. Am I right?
     
  2. jcsd
  3. Dec 28, 2012 #2
    Re: What do we mean when we say "1 kg of bananas"?

    The weight of the bananas is a force as you said, forget that for this question, that increases as the force of gravity increases according to w=mg. The question is talking about the mass of the bananas, which is always 1 kg whether your on the moon or on earth so yes you do get the same amount.
     
  4. Dec 28, 2012 #3

    TSny

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    Homework Helper
    Gold Member

    Re: What do we mean when we say "1 kg of bananas"?

    Yes, you're right. And I think you should throw 1 kg of tomatoes at your teacher for asking this ambiguous question! [Of course, it's not really ambiguous if the supermarkets on the moon have properly calibrated their spring balances.]
     
    Last edited: Dec 28, 2012
  5. Dec 28, 2012 #4
    Re: What do we mean when we say "1 kg of bananas"?

    LOL =)
    Funny task:)
     
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