Need !
in a system, when energy is transformed from one form to another,
all energy changes to friction.
new energy is created.
the total energy is conserved.
some energy is always destroyed.

   Energy transformation is the process of changing energy from one form to another. This process is happening all the time, both in the world and within people. When people consume food, the body utilizes the chemical energy in the bonds of the food and transforms it into mechanical energy, a new form of chemical energy, or thermal energy.