11.3 Pressure

As a woman walks, her entire weight is momentarily placed on one heel of her high-heeled shoes. Calculate the pressure exerted on the floor by the heel if it has an area of $1 . \text{50} \text{cm}^{2}$ and the woman’s mass is 55.0 kg. Express the pressure in Pa. (In the early days of commercial flight, women were not allowed to wear high-heeled shoes because aircraft floors were too thin to withstand such large pressures.)

Nail tips exert tremendous pressures when they are hit by hammers because they exert a large force over a small area. What force must be exerted on a nail with a circular tip of 1.00 mm diameter to create a pressure of $3 . \text{00} \times \text{10}^{9} \text{N}/\text{m}^{2} ?$(This high pressure is possible because the hammer striking the nail is brought to rest in such a short distance.)