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How much weight can a given cork object hold afloat in water

  1. Jun 15, 2015 #1
    I know there may be different types of cork, but let's take the "average" cork used for cork board, at say, 0.24gm/cm^3. Let's say you make a boat out of that cork. I understand that the weight of water displaced should be greater than the object's total weight (e.g. density of cork less than the 1 gm/cm^3 of density of water). If cork's density is 0.24gm/cm^3, will cork hold something about 4 times its weight = three times greater added? Is it just the weight density equation, where weight density = weight/volume, and as long as the total density (cork weight + object weight)/(cork volume + object volume in water) is equal to or less than the density of water it displaces, then the buoyant force will keep it afloat? < Can I add the weights and density like I show to get the total density?

    Thanks in advance!
    Last edited: Jun 15, 2015
  2. jcsd
  3. Jun 15, 2015 #2


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    I'm assuming you mean a raft made of cork, and not a boat (which can hold more because of the cup shape). It depends on what you mean by afloat. Is it afloat if the cork is completely submerged, but the object on top of the cork is still floating? In that case, just take the average density of cork+load and compare it to the average density of the water. If you want to keep the load dry, then take the total weight divided by the cork volume, and compare it to the water density.
  4. Jun 15, 2015 #3


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    and apart from what khashishi said

    what you have asked is akin to asking " how long is a piece of string?"

    you told us nothing about the size, area/volume of the bit of cork ... a few cubic cm ? a metre square and a metre thick or large area and thin ????

    all variations will hold different amounts

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