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# Physics/hitting power

Question
Becuase I am not person who learned physics, I actually don't know what kinds of information is needed.
What I could guess is
Sharpeness is almost same with the needle point or lancet point..
And speed is 70cm/s and distance is 20cm.
if I know the power which that particle has... I could understand that why needle or wood particle almost could not possible to be stucked in the skin or in the layer of inner heart by the flowing blood.
Becuase there is alof of data for power which needle must have when needle inject into skin.

P.S and would you pls. let me know the power which liquid hasT on the surface of diameter of 0.7mm (speed is 70cm/s and distance is 20cm)

Thank you very much.

Speed and distance are not power.  Power is an amount of work done per unit time.  Power is unrelated to whether or not a sharp point can penetrate a surface.  That depends on the force per unit area (and that area can be ridiculously tiny at the point of a needle) and the properties of the surface material itself.  I'm telling you that with the information you have the problem is simply not solvable.  This is one follow-up on this question too many, and I still haven't the faintest idea why you're asking it.  If I knew the situation I was trying to solve a problem for, I might be able to help.  Barring that, I can't help you any further because a particle of wood inside someone's blood stream is a very ridiculous scenario to begin with.

Physics

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#### Dr. Stephen O. Nelson

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