Skip to main content

An advertisement states that a machine with moving parts will continue moving forever without having to add any energy. Can this be correct? Explain.

Your question is asking about complete conservation of energy within a machine. Whenever there are moving parts in a machine, this is an impossibility.


Although the First Law of Thermodynamics states that energy cannot be created or destroyed in an isolated system, a machine isn't capable of retaining this energy (at least not with today's technology).  The problem lies with non-conservative forces--those that are path-dependent.  A common example of this is friction.  The amount of...

Your question is asking about complete conservation of energy within a machine. Whenever there are moving parts in a machine, this is an impossibility.


Although the First Law of Thermodynamics states that energy cannot be created or destroyed in an isolated system, a machine isn't capable of retaining this energy (at least not with today's technology).  The problem lies with non-conservative forces--those that are path-dependent.  A common example of this is friction.  The amount of work done by a non-conservative force depends on what pathway it takes.  Think of rubbing your hands together.  The more you rub them, the more work it takes, and the greater amount of energy lost you will experience as heat.  


It is important to understand that work and energy can be looked at as very similar ideas.  Doing work to an object (applying a force resulting in movement in that direction) will result in a change in the energy that object has.  


In a machine, work is achieved from something like a battery, a spring you wind up, or something along those lines.  The machine is only capable of doing what it was designed to do with the work that was input.  As soon as materials come in contact, friction will result.  You hear this as sound.  Sound takes energy to create, and that energy is effectively "stolen" from the machine, never to return.  And this is only one example of the wasteful energy that machines must contend with.


So, unless the technology has some nifty way of recuperating that energy (and engineers work every day to do this!), the advertisement cannot be correct.

Popular posts from this blog

In chapter one of The Great Gatsby, what advice does Nick's father give him? How does this make him a good person to tell this story?

Nick says that his father advised him that, before "criticizing anyone," he "remember that all the people in this world haven't had the same advantages" as Nick.  As a result, Nick claims that he is "inclined to reserve all judgments," presenting himself to the reader as a fair and dispassionate arbiter of character, and thus, a reliable narrator.   The problem is that Nick immediately reveals himself as anything but reliable, as he then launches... Nick says that his father advised him that, before "criticizing anyone," he "remember that all the people in this world haven't had the same advantages" as Nick.  As a result, Nick claims that he is "inclined to reserve all judgments," presenting himself to the reader as a fair and dispassionate arbiter of character, and thus, a reliable narrator.   The problem is that Nick immediately reveals himself as anything but reliable, as he then launches into a discussion of how pe...

How and why does James Gatz become Jay Gatsby? Describe the young Gatsby/Gatz.

James Gatz, a poor Midwestern boy of probable Jewish lineage, becomes Jay Gatsby, a presumed WASP and wealthy socialite, when he moves to New York City and acquires his fortune. It is wealth that has allowed Gatz to transform himself into Gatsby. However, those who know his background (e.g., Daisy and Tom Buchanan) never allow him to forget that he is nouveau riche -- that is, an upstart who has just recently made his fortune,... James Gatz, a poor Midwestern boy of probable Jewish lineage, becomes Jay Gatsby, a presumed WASP and wealthy socialite, when he moves to New York City and acquires his fortune. It is wealth that has allowed Gatz to transform himself into Gatsby. However, those who know his background (e.g., Daisy and Tom Buchanan) never allow him to forget that he is nouveau riche -- that is, an upstart who has just recently made his fortune, whereas they arose from well-to-do families. Gatz became Gatsby through determination and discipline. At the end of the novel, the narr...

Explain and discuss how the definitions of freedom change for the nation, for the freedmen and for southern whites after the Civil War.

After the Civil War, the definition of freedom changed in the nation, as slavery was ended with the 13th Amendment to the Constitution in 1865. The practice of slavery was disallowed, but definition of the freedom that would take its place was a subject of controversy, ongoing debate, and even violence in the decades to come.  For freedmen, freedom often meant reconciling with their families, who were broken up by slavery; choosing which church to... After the Civil War, the definition of freedom changed in the nation, as slavery was ended with the 13th Amendment to the Constitution in 1865. The practice of slavery was disallowed, but definition of the freedom that would take its place was a subject of controversy, ongoing debate, and even violence in the decades to come.  For freedmen, freedom often meant reconciling with their families, who were broken up by slavery; choosing which church to belong to without being ordered to attend religious services (or not to attend) by their mast...