Perfect machine is not possible in real life, why?​

A perfect machine is not possible because perfect machines mean that the system will always perform at a 100% efficiency, and that's not possible in real life because the systems of the real world will always lose some energy in the form of heat, resulting in a lower efficiency percentage.

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.