I was wondering if someone could help me with a demonstration I have had
trouble with. I place a block of wood on a tilted desk and tilt it to
the angle that just makes the block move and secure the desk. Then I put
the block on another edge (with a different surface area) to show that the
frictional force and the coefficient of friction do not change with
surface area. The problem is that the block always stays put on the side
with the large surface area and slides on the side with the small surface
area. Any explanations? Thanks in adavance for any help.