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.

Comments

Post a Comment

Popular posts from this blog

What is the meaning of "juggling fiends" in Macbeth?

Macbeth is beginning to realize that the three witches have been deceiving him since he first encountered them. Like jugglers, they have kept changing their forecasts in order create confusion. This is particularly apparent when the Second Apparition they raise in Act IV,   Scene 1 tells him that no man of woman born can overcome him in hand-to-hand battle--and then Macbeth finds himself confronted by the one man he has been avoiding out of a... Macbeth is beginning to realize that the three witches have been deceiving him since he first encountered them. Like jugglers, they have kept changing their forecasts in order create confusion. This is particularly apparent when the Second Apparition they raise in Act IV,   Scene 1 tells him that no man of woman born can overcome him in hand-to-hand battle--and then Macbeth finds himself confronted by the one man he has been avoiding out of a sense of guilt, and that man tells him: Despair thy charm. And let the angel whom thou still hast serve...
Post a Comment
Read more

In Martel's Life of Pi, how does writing a diary help Pi Patel build on his leadership skills?

At the end of chapter 73, Pi first divulges the fact that he had started a diary after about a week alone at sea. Pi claims that he wrote about "practical stuff" (208) such as what he caught for food, foreseeable problems and solutions, Richard Parker, and reflections about specific events that occurred. In a sense, Pi is the captain of his ship; therefore, he must take responsibility for himself and his crew. He can... At the end of chapter 73, Pi first divulges the fact that he had started a diary after about a week alone at sea. Pi claims that he wrote about "practical stuff" (208) such as what he caught for food, foreseeable problems and solutions, Richard Parker, and reflections about specific events that occurred. In a sense, Pi is the captain of his ship; therefore, he must take responsibility for himself and his crew. He can do this by writing down events, problems and solutions, and reflections to look back on when confronted with repeated problems. It can ...
Post a Comment
Read more

Discuss movements that were inspired by the Civil Rights Movement and list one success for each group.

African-Americans contributed in a very big way during World War II. These contributions were demonstrated at home and on the battlefield. After the war, African-Americans properly felt it was time for them to achieve equality with white Americans. During the 1950's, the modern Civil Rights Movement was born and it had a number of successes (integration of the military and Brown vs. Board of Education as examples.) This success inspired other activists to demand change... African-Americans contributed in a very big way during World War II. These contributions were demonstrated at home and on the battlefield. After the war, African-Americans properly felt it was time for them to achieve equality with white Americans. During the 1950's, the modern Civil Rights Movement was born and it had a number of successes (integration of the military and Brown vs. Board of Education as examples.) This success inspired other activists to demand change for their agendas. Two examples of moveme...
Post a Comment
Read more