Question

While it’s impossible to design a perpetual motion machine, that is, a machine that keeps moving forever, come up with ways to keep some type of periodic motion going for a very long time. Explain the limits on perpetual motion. Discuss what slows down a machine and how you might minimize those effects for at least one specific form of periodic motion, such as the motion of a spring or pendulum, or circular motion. Come up with an inventive solution!

Answer 1

A perpetual motion machine is (as the name implies) a machine that moves perpetually; it never stops. Ever. So if you created one today and set it going, it would keep on going until the Big Freeze. Calling that “a long time” is an understatement of epic proportions

Answer 2

Answer:

We can not create a perpetual motion machine because this kind of motion violates two laws of thermodynamic.

Explanation:

We can not create a perpetual motion machine because this kind of motion violates two laws of thermodynamic.

1. In any isolated system we can not create and destroy energy, it is a law of conservation of energy, all the energy is transformed, so the thermal efficiency, that is the produced work divided by the input heating can not be greater than one.

A perpetual motion machine needs to create energy to remain its movement constant along the time.

2. The second law of thermodynamic is related to the entropy, it is always positive. A natural process runs only in one sense, and is not reversible. Therefore the output work power of heat of a engine for instance is always smaller than the input heating power ans the rest of the heat energy supplied is wasted as heat to the ambient surroundings. The thermal efficiency has a maximum, given by the Carnot efficiency, which is always less than one.

That is way we can not create a perpetual motion machine.  We can create a machine that minimize those effects and maximize the efficient. We can reduce the air resistance for example.

I hope it helps you!