This document defines pressure as force per unit area, with pressure measured in pascals (Pa) and force in newtons (N). It provides the formula for calculating pressure as pressure = force/area. It explains that cutting tools increase pressure by reducing the contact area, while caterpillar tracks reduce pressure from heavy vehicles by increasing their surface area and distributing the force over a larger area.

1. Pressure
Pressure under a solid

2. What is pressure?
 Defined as the force per unit area.
 Force is measured in newtons
(N), area is measured in square
metres (m2).
 Pressure is measured in pascals
(Pa), where 1 Pa is equivalent to
1N/m2.

3. Calculating pressure
 Pressure (p), force (F) and area (A)
are linked by the following equation:
pressure, p force, F F
p
area, A A

4. Formula triangle
If a question asks you
to write out the formula
for calculating
F pressure, do not use
the triangle – WRITE
OUT THE FORMULA!
p x A

5. Using pressure
 Some machines, particularly those
used for cutting, need to exert a high
pressure; how do they do that?
 In other areas, a low pressure is
important. Can you think where this is
the case and how do they manage it?

6. Using pressure
 Cutting tools  Caterpillar tracks
increase the are used to reduce
pressure by being pressure from
sharp. heavy vehicles on
 This reduces the the ground.
area and so makes  They do this by
the pressure higher increasing the area
for any given force. so lowering the
pressure for any
given force
(weight).

7. lets look at that
again..

8. What is pressure?
 Defined as the force per unit area.
force per unit area.
 Force is measured in newtons
newtons (N),
(N), area is square metres (m2).
measured in square
metres (m2). pascals (Pa),
1N/m2.
 Pressure is measured in pascals
(Pa), where 1 Pa is equivalent to
1N/m2.

9. Calculating pressure
 Pressure (p), force (F) and area (A)
are linked by the following equation:
pressure, p force, F F
p
area, A A

10. Formula triangle
If a question asks you
to write out the formula
for calculating
F pressure, do not use
the triangle –
WRITE OUT
THE FORMULA!
p x A

11. Using pressure
 Some machines, particularly those
high
used for cutting, need to exert a high
cutting,
pressure; how do they do that?
low
 In other areas, a low pressure is
important. Can you think where this is
the case and how do they manage it?

12. Using pressure
 Cutting tools  Caterpillar tracks
increase the reduce
are used to reduce
pressure by being
sharp. pressure from
sharp.
reduces heavy vehicles on
 This reduces the ground.
the ground.
area andhigher
so makes  They do this by
force.
the pressure higher increasing the area
for any given force. so lowering the
lowering
pressure for any
given force(weight).
(weight).