Pressure and Moments
A brief PowerPoint to describe my
understanding of Pressure and
Items that cause high and low pressure.
• Stiletto heels - Pumps.
• Beanbag - Chair.
The pressure formula
Pressure (the symbol: P) is the force per
unit area applied in a direction
perpendicular to the surface of an
object. Gauge pressure is the pressure
relative to the local atmospheric or
The diagram at right shows a sharp knife and a dull knife in contact with a
surface (maybe a nice, juicy steak!). You know that the sharp knife cuts more
efficiently - Why?
Notice that the sharp knife has a very small area of contact with the surface,
while the dull knife has a much larger area of contact. If both knives are
pushed down with the same force, the sharp knife will exert a much greater
pressure on the surface than the dull knife - and pressure cuts.
So, if you are "stuck" with a dull knife, you have to exert much more force in
order to generate enough pressure to cut your steak, right?
Force multiplied distance from pivot
equals turning moment.