Difference between structure & machine

The following differences between a machine and a structure are important from the subject point of view:

1.  The parts of a machine move relative to one another, whereas the members of a structure do not move relative to one another.

2.  A machine transforms the available energy into some useful work, whereas in a structure no energy is transformed into useful work.

3.  The links of a machine may transmit both power and motion, while the members of a structure transmits forces only.