Question

A rectangular block of side 20 cm into 10 cm applies a force of 70N. Calculate the pressure exerted by the block on ground.

Answer 1

Solution - 

Given  :   Mass of iron block, m = 10 kg
                Acceleration due to gravity, g = 10 m/s2
so ,           weight of iron block, W  = m x g 
                                                  = 10 x 10 = 100 N

so we can say force exerted by the iron block on the table top = 100 N

a ) 1st case -                    F = 100 N
                                  Area = 20 cm x 10 cm 
                                         = 20 /100 m x 10 / 100 m
                                         = .02 m2

we know, Pressure = Force /Area
                           = 100 / .02 Pascal

                           = 5000 pa 

b) 2nd case -                  F = 100 N
                                   Area = 10 cm x 5cm 
                                         = 10 /100 m x 5/ 100 m
                                         = .005 m2

we know, Pressure = Force /Area
                           = 100 / .005 Pascal

                             = 20000 pa