Question

OSHA recommends that walking and working surfaces have a static coefficient of friction of 0.5. Slip resistant flooring material such as textured, serrated, or punched surfaces and steel grating may offer additional slip resistance. A wet and greasy steel-grating floor has a coefficient of friction between a 110 kg worker’s work-boot soles and the steel grating of 0.35. a. What is the maximum static force of friction required to keep the worker from slipping on this wet and greasy steel-grating walking and working surface?

Answer 1

The force of friction is directly proportional to normal reaction

Here normal reaction force is N=mg

Therefore the frictional force

The maximum static firctional forictional force is called limiting friction at which the body bigins to move.

the kinetic frictional force is constat at whch the body is in motion. The kinetic frictinal force is less then static frictional force.

Therefore static frictional force is

And that of kineytic friction is

which is less than static friction. Hence the first case is better to walk.