a. In a nail bed, the weight is evenly distributed among numerous nails, so that the pressure exerted by each nail is not enough to puncture a person’s skin. If its only a single nail, the entire force created by the weight of the body would be distributed over a very small area presented by the tip of one nail. In this case the force per unit area will be great and can puncture the skin.
b. Knives and axes are sharpened because when the area decreases the pressure increases. Hence a small force is enough to cut an object.
c. As area increases pressure decreases. So weight of the truck exerts less pressure on the road.
