A man is carrying a bucket with water. If a object is kept in it which floats in water, man will feel
1) heavier
2) lighter
3) none
I think when the body floats its weight is balanced by upthrust so no further be felt. Is it right or wrong?
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+1 This is not such a bad question that should earn -5. This can be changed into a conceptual problem. – ABC May 30 '13 at 12:57
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1@userØØ7: The way it's been defined makes it appear bad. In fact, all questions get downvotes for the same reason. It's like a restatement of some exam-type question (directly asking) which disagrees with our FAQ ;-) – Waffle's Crazy Peanut May 30 '13 at 16:15
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Duplicate of http://physics.stackexchange.com/q/62864/11062 – Waffle's Crazy Peanut May 30 '13 at 16:24
2 Answers
2
The man will have to carry the extra weight.
The object floats on the water, because the forces on it balance out. Gravity pulls the object down, the water pushes it up.
Now hold part of that thought:
The object pushes against the water.
The water pushes against the bucket.
The man is using force to hold the bucket.
Thus the bucket and its content are heavier when you add extra stuff to it. (Even if it floats).
Not using answer 1) because The man feels heavier is a bit weird way to say that. The bucket the man is carrying is heavier. The man himself did not change.
Hennes
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1
The answer is 1.
The total weight of is that of the man, the bucket, the water and the wood. The fact that the wood displaces more water than its own weight does not change its weight. That just explains why it floats.
Try it yourself. Stand on scales with a bucket of water, then lift a block of wood and see the weight change. Finally, put the wood in the water and ther will be no further change at all.
hdhondt
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