Changing Pressure

High pressure can be an advantage or a nuisance. Wide tyres reduce pressure. Pressure helps vehicles to stop and prevent them from sinking into mud and snow. Tracks on the vehicles also do the same jobs- help vehicles to stop and prevent them from sinking into the mud and snow. By wearing snowshoes can made life easier to walk in deep snow. They spread a person's weight over a much bigger area than normal shoes. Pressure can be increased by making the area that the force presses on smaller.

Example 1:
An elephant weighing 40000N stands on one foot of area 1000cm
2(=1/10m2). What pressure is exerted on the ground?
Formula first: pressure = force/ area
Then put in the numbers=40000N/1/10m
2
=40000 X 10N/m
2
=400000N/m
2

Example 2:
What is the pressure exerted by a girl weighing 400N standing on one 'stiletto' heel of area 1cm2(=1/10000 m2)?
Formula first: Pressure = force/ area
=400N/1/10000m
2
=400 X 10000 N/m
2
=4000000 N/m
2(ten times bigger)
So, the elephant exerts a larger force (because of it is heavier) but the girl's heel exerts a larger pressure (because of its smaller pressure area).

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