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Author Topic: Do the heat from dolphin's body really helps them reduce the drag force?  (Read 1983 times)

Offline Cham

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I got a project about animal + physic(i choose drag force). So, i just wanna know could the body temperature of the dolphin helps reduce the drag force when they swim? Is this theory true? cause i just assume it by connecting the concept of viscosity with concept of drag. Please help me..give me some hint guys!!!!


 

Offline Don_1

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Since Dolphins can reach up to 30 MPH I rather doubt that their body temperature would be of any great assistance in reducing drag.

Gray's Paradox said that Dolphins had to have some skin property which reduced drag, since the animal did not have the strength to power itself at such great speeds. It was suggested that the dolphin sheds it's skin at a tremendous rate, thus reducing drag. However, it has recently been discovered that the dolphin is very much more powerful than had previously been thought.

Research has shown that the dolphin's tail can exert up to 1,800 Newtons, 10 times the force they were previously thought to be capable of.
 

Offline Cham

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ok thanks 4 tht info..but i still cant get it..i even search in the internet and no result about the concept bout heat tht can reduce the drag. 1 more question: is it true that a hot bullet travel faster than the cold 1?
 

Offline Don_1

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I would think all bullets would be pretty damn hot once fired.

But in answer to the question do hot objects have less drag, take a look at this:

http://www.thenakedscientists.com/forum/index.php?topic=34376.0
 

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