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Energy Form
Gravitational Potential
Energy
Kinetic Energy
Elastic Potential
energy
Heat (Thermal) Energy
Electrical Energy
Chemical Energy
Sound Energy
Electromagnetic waves
Nuclear Energy
Description/Summary
An object placed at a height above the
“ground” has Gravitational P.E.
A moving object has Kinetic Energy.
Any material that is stretched or
compressed stores elastic potential
energy due to the change of position of
the atoms.
Atoms and molecules in any material
vibrate or move faster when heated.
Heat can be described as the
Vibrational KE and PE of the atoms.
Electricity is a flow of charge due to a
battery providing a voltage.
Chemical energy is the energy stored
in the bonds between atoms. A
chemical reaction breaks bonds and can
release this energy.
Vibrations passed on between atoms in
a material we can hear as sound.
Light, radio, X-rays etc. all carry energy
from one point to another.
Energy stored in the nucleus of atoms.
Example
Water in a high
reservoir has lots of
G.P.E.
A fast moving truck
has a lot more KE
than a slow moving
car.
A wound up clock
spring or a stretched
rubber band.
The steam in a steam
engine is very hot and
when released can
move the pistons.
A flow of electrons in
a wire.
The chemical inside
batteries store energy.
Fuels such as oil store
energy.
A vibrating string can
cause sound.
Light from the Sun
reaches us as Light
and IR Radiation
Fission bomb
 If an object has energy then it possesses the ability to do work.
 The basic unit of energy is the Joule (J).
Energy is of no use to us unless we can transfer it from one form to another
form and in the process do some “work”.
Chemical
Energy
Heat and Light
Energy
Force
Birthday
Present
Distance Moved
 Whenever a force moves an object through a distance some energy is
transferred to the object by the force.
 The energy transferred is called the Work Done by the force.
Work Done =
Energy transferred in
Joules
Force
x
Distance
Distance moved in the
direction of the force
measured in metres
Applied force in
Newtons
Note. If the force does not move then no work is done.
Examples
1. A constant force of 25 Newtons is
required to push a lawnmower at a
constant speed for a distance of 4 m.
(a) Calculate the work done by the
person.
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25N
4m
(b) If the work done is the energy transferred by the force, where did the
energy come from?
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2. A weight lifter exerts a force of 2000 Newtons in
order to raise the weight through a vertical
distance of 2.5 m.
Calculate the amount of work done by the
weightlifter on the weights.
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3. A forklift truck lifts a box of weight 500 N
through a distance of 4 m.
(a) What upwards force does the truck
need to apply to the box in order to lift the
box at a constant speed?
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___________________________________
(b) Calculate the work done by the upward force of the truck.
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4. A 10 Kg mass is lifted through a vertical distance of
0.5 metres.
10Kg
0.5m
(a) Given that that g = 10 N/Kg calculate the weight of
the mass.
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____________________________________________
(b) What average force must be applied in order to lift the object through this
distance? ______________________________________________________
(c) Calculate the work done by the person when lifting this object.
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