Pressure at a point 
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 Pressure at a point : it's the average force acting normally on unit area at this point it is measured in N/m^2  or  Pascal
P= force exerted/area in contact = F/A = mg/A
If the force is making an angle q with the normal,
therefore, the perpendicular component of the force = F cos q   or  P = F cos q/A
N/m^2 = j/m^3                                              

Where q is the angle between the acting force and the normal to the area

Factors affecting the Pressure at a point :
P a F at a constant A     &   P a 1/A at constant F

Q. What's meant by the pressure at a point = 10^5 Pascal ?
It means that the average force acting normally on unit area at this point = 10^5 N

Q. Nails, drawing pins have pointed edges and Knives have sharp edges ?
To decrease the acting area ( area in contact ) in order to increase the pressure, so they can penetrate objects easily  P a  1/A

Q. Camels have broad pads and tanks have broad caterpillars ?
To increase the acting area in order to decrease the pressure, so they can walk on and without sinking.

More Questions ? go to Physics in life