Pressure
Force
Area
(N/m )
Pressure
kg m/s
m
2
2
4 2
60 81
1 10
588
.
Work done
Suppose broken-down motor car was pushed along road, work
would done the car applying the force necessary move along the
road. kN/m2
These two examples show that the young woman exerts times more pressure the
ground than the elephant.
● ‘Electrical force’ the force created electrical field.81m/s2
).
Pressure
Force
Area
(N/m )
Pressure
kg m/s
m
2
2
4 2
1000 81
400 10
.
. This because her mass exerts force over much smaller area
than the elephant’s foot and the reason why many wooden dance floors are damaged by
high-heeled shoes. hands would apply pressure the body
panel the point contact with the car.
● ‘Cohesive adhesive force’is
the force required hold things
together.
● ‘Shearing force’is the force which
moves one face material over
another.81m/s2
. Calculate the pressure exerted the shoe the floor (assuming the
acceleration due gravity 9.
●
‘Electrical force’is the force created
by electrical field.
245 3
.
● ‘Centripetal force’ the force acting towards the centre when mass
attached string rotated circular path. Pressure stress measure of
the force per unit area.
Pressure stress
Force
Area
N/m
)
2
Example 1
A young woman mass 60kg puts all her weight the heel one shoe which has
an area 1cm2
.
● ‘Friction force’is the force which
resists prevents the movement
of two surfaces contact.
● ‘Magnetic force’is the force
created magnetic field. Calculate the pressure exerted the elephant’s foot the floor,
assuming the acceleration due gravity 9.
● ‘Gravitational force’ the force acting towards the centre the
earth due the effect gravity.
● ‘Gravitational force’is the force
acting towards the centre the
earth due the effect gravity.
Definition
Pressure stress measure the
force per unit area.
Definition
● ‘Inertial force’is the force required
to get things moving, change
direction stop, like the motor
car discussed above.
● ‘Tensile force’is the force pulling
things apart.
● ‘Magnetic force’ the force created magnetic field.
● ‘Centrifugal force’ the force acting away from the centre, the oppo-
site centripetal force.
Pressure stress
To move broken-down motor car might exert force the back the
car propel forward.
● ‘Centripetal force’is the force
acting towards the centre when
a mass attached string is
rotated circular path.Basic electrotechnical units and theory
87
● ‘Shearing force’ the force which moves one face material over
another. Heavy breathing and perspiration would evidence the work done.
● ‘Compressive force’is the force
pushing things together.
● ‘Centrifugal force’is the force
acting away from the centre, the
opposite centripetal force.
6
6 2
kN/m
Example 2
A small circus elephant mass tonne (1000kg) puts all its weight one foot which has
a surface area 400cm2
