IGCSE
Physics Notes: Conservation of Energy – Transforming Energy From
One Form to Another
There are lots of different
types energy:
Kinetic, gravitational,
chemical, heat and many more.
It is one of the the
fundamental principles of physics that energy is conserved. When any
energy transfer takes place, the energy we start with is transformed
into some other form of energy. The energy never goes nowhere. If
some of the energy appears to be wasted, then that energy has been
sed to overcome forces like air resistance or friction. If this
happens some energy has become internal energy of some substance, but
it has not gone “nowhere”.
For each form of energy
there are equations to tell us how much energy there is. If a body of
mass m is moving with velocity v then it has kinetic energy and the
amount of kinetic energy is given by
If a body of mass m is at a
height h above the floor then it has gravitational potential energy
and the amount of gravitational potential energy is given by
In the diagram below, as the
skateboarder moves from position 1 to 2, his kinetic energy changes
into potential energy. At 3, all the kinetic energy the skateboarder
had initially has been changed into kinetic energy. The situation
below has been idealised. In fact there is friction which must be
overcome, and the skateboarder's potential energy at 3 will be less
than that show. In practice this will mean he will not rise to a
height of 3.27m.
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