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Penny Drop (Posted on 2013-01-17) Difficulty: 1 of 5
A toy wooden canoe is floating in a swimming pool.

Which will raise the level of the water in the pool higher:
Dropping a penny into the pool or, dropping the penny into the canoe?

No Solution Yet Submitted by K Sengupta    
Rating: 3.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re(2): Eureka! | Comment 3 of 6 |
(In reply to re: Eureka! by brianjn)

"It doesn't matter whether the penny is dropped into the water or the canoe, the water will rise according to the mass of the penny."

Suppose you made a coin the size of a penny but made of a material much denser than the copper or alloy that the penny is made of (they use a lot of zinc nowadays, at least in the U.S.A.). Both the original copper penny and the heavier gold piece of the same size will have the same volume and can displace no more water for all the extra weight of the latter. When placed in a boat however, the boat sits lower in the water with the extra weight and so displaces more.

A floating object will displace its weight of water, while a sunken object will displace only its volume. A penny sinks, as it's denser than water, and as such, it displaces less when sunk than when on the boat.

  Posted by Charlie on 2013-01-17 20:31:49
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