The Laws of Thermodynamics Govern Energy Flow
In the case of a bow and arrow, the energy
is converted from the potential energy in the
archer's arm to the potential energy in the bent
limbs of the bow when the string is drawn back.
When the string is released, the potential energy
in the bow limbs is transferred back through
the string to become kinetic energy in the arrow
as it takes flight.
Kinetic energy: energy due to motion.
The cars of a roller coaster reach their
maximum kinetic energy when at the bottom
of their path. When they start rising, the kinetic
energy begins to be converted to
gravitational potential energy. The sum of
kinetic and potential energy in the system
remains constant, ignoring losses to friction.
1st Law of Thermodynamics: energy can't be created or destroyed but can be converted from one form to another.
2nd Law of Thermodynamics: when energy is transferred or transformed, part of the energy assumes a form that can't pass on any further.