A careless workman is working on a weak factory roof, when he falls through the roof and is caught by his arms.

A rescuer is worried about falling through the roof himself he decides that the only safe way of reaching the worker it to put a wide plank of wood, or another ladder, across the roof and to crawl over that.

Explain in terns of pressure why is this a good idea?

Question

A careless workman is working on a weak factory roof, when he falls through the roof and is caught by his arms.

A rescuer is worried about falling through the roof himself he decides that the only safe way of reaching the worker it to put a wide plank of wood, or another ladder, across the roof and to crawl over that.

Explain in terns of pressure why is this a good idea?

jamesj · Answer

The ladder touches the roof in many places and in short the area of contact between the ladder in total is greater than would be a footprint or two.

Hence, because pressure = (force)/(area), the pressure due to the fireman's weight is less on any individual spot on the roof than it would be if he did not use the ladder.

Make sense?

anonymous · Answer

Yes thanks alot,

anonymous · Answer

his weight is distributed along the roof than rather be concentrated where his feet are