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A block of wood of mass 5 kg and dimensions 40 cm x 20 cm x 10 cm is placed on a table top. Find the pressure exerted if the block lies on the table top with sides of dimensions i) 40 cm x 10 cm ii) 40 cm x 20 cm

The mass of the wooden block = 5 kg
The dimensions = 40 cm x 20 cm x 10 cm
               Thrust = F = m x g   
                                 = 5 kg x 9.8 m/s2
                                 = 49 N
i) Area of a side = length x breadth
                       = 40 cm x 10 cm
                       = 400 cm2
                       = 0.04 m2
         Pressure = 49 N/ 0.04 m2  
                       = 1225 N/m2
ii) When the block lies on its side of dimensions 40 cm x 20 cm. It exerts the same thrust.
Area of a side = length x breadth
                       = 40 cm x 20 cm
                       = 800 cm2
                       = 0.08 m2
         Pressure = 49 N/ 0.08 m2  
                       = 612.5 N/m2


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