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. PRESSURE.

A solid resting on a horizontal surface exerts a normal contact force equals to its weight. The pressure of the solid on the surface depends on the area of contact (A) and the weight (force)..

Factors Affecting Pressure in Solids Weight of the solid (force) If the area of contact between solid and surface is constant, pressure increases with weight. Area of contact of the solid with surface. The smaller the area, the higher the pressure if same force is applied. Therefore pressure can be reduced by increasing the area of contact ..

A man whose mass is 90kg stands on a floor.. P= F/A = 900N/0.0368m 2 =24,456.5217N/m 2 ..

2. A block of a soap stone of dimension 4m by 2m by 3m is 48kg and is made to rest on a smooth horizontal surface a) Calculate the minimum pressure it exerts on the surface. b) Calculate the maximum pressure it will exert on the surface.

Pressure in fluids A fluid is a term that refers to either liquids and gases. The set up below can be used to illustrate pressure in fluids:.

A diver under water experiences pressure due to the weight of water above him plus the atmospheric pressure above the water surface. The deeper the diver, the greater the pressure..

. It is thus clear that pressure in fluids is directly proportional to the height of the column h, the density of the fluid ρ and the gravitational field strength g..

1. A diver working under water is 15 m below the surface of the sea. Calculate the pressure due to water experienced by the diver (take g=10N/kg) and density of sea water to be equal to 1.03g/cm3. P = hρg =15 m×1030 kg/m^3×10 N/kg =154500 N/m^2.

Next lesson we shall go through. Transmission of pressure in fluids.

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