A girl is wearing a pair of flat shoes. She weighs 550 N. The area of contact of one shoe with the ground is 160 cm2. What pressure will be exerted by the girl on the ground?
(a) If she stands on two feet?
(b) If she stands on one foot?
Force, F = 550N Area of contact of one shoe = 160 cm2 = 160 x 10-4 m2
Area of contact with two shoes = 160 x 2 = 320 cm2 = 320 x 10-4 m2
(a) If the girl stand on two feet, Pressure = 
= 550/ 320 * 10-4
= 17187.5 N/m2
(b) If she stands on one foot, Pressure = 
= 550/ 160 * 10-4
= 34375 N/m2
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