a) Consider when a person slips because there is a thin film of water between their shoe and the floor. Assume that the film must remain larger than the roughness for 1 second for a person to slip. Using the squeeze film theory find the minimum thickness of the film, above which a person will slip. Other information: Shoe surface area: 9"x3", Roughness=1 micron, weight = 500 N. Use viscosity of water at room temp.
b)Also discuss the concept of then having rough surfaces to reduce slipping (such as the differences between a waxed tile floor, concrete, and textured concrete (no calculations needed here).