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General Physics

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 Joined: 18 Oct 2011 Post: 9
10 Jun 2012 20:26:31 IST
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Force and Pressure
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It is easier to cut with sharp knife than blunt knife?

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Joined: 1 Apr 2012
Posts: 381
10 Jun 2012 21:53:05 IST
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When using a knife, you put the knife on a surface that needs to be cut, and then you apply a force on the knife. This force that you are applying on the knife puts pressure on the knife, which also puts pressure on the thing that's being cut. When you rest the knife on the cutting surface, without applying force, only a certian portion (A) of the total area of the blade touches the cutting surface. The sharper a knife, the smaller the area (A) of the knife. P = F/A According to the formula above for pressure, the smaller the area (A), the greater the pressure that can be exerted. Since the area (A) corresponds to the sharpness of the knife, the sharper the knife, the greater the pressure that can be exerted. This makes it easier to cut things.***like my answer***

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Joined: 29 Dec 2006
Posts: 5524
11 Jun 2012 12:43:34 IST
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For cutting something we have to apply a given amont of pressure. Pressure = force/area. For a sharp knife area on which force is applied is less and hence same pressure can be applied with small force. You  can cut it with blunt knife also but for that you have to apply lot more force.

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