Mechanical Engineering Community

# Questioning Conservation of Energy

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Very few scientists dare to doubt conservation of energy, doing so destroys reputation and carrier. Nevertheless, let’s take a chance.

"This law of conservation of energy is not something we have derived from basic physics principles. Rather, it is a law based on countless experiments. Scientists and engineers have never found an exception to it. Energy simply cannot magically appear or disappear." (Jearl Walker, David Halliday, Robert Resnick (2014) Fundamentals of Physics, tenth edition, Cleveland State University, Pages 195-196)

Being kids we all played with a gyroscope and you must remember how much harder it is to tilt or flip a rotating toy than a non-rotating one. Now let’s think like adults. The only difference between resting and rotating gyroscopes is the rotation. In this particular case, RPM is proportional to kinetic energy. So when we flip it some of that energy must be lost due to resistance to our hands. This is what conservation of energy is about.

Description of the test:  Two identical gyroscopes with equal RPM one left along to come to its full stop another we flip and turn over and tumble until it stops (one gyroscope will suffice either). Conservation of energy tells us that the one left along must take more time to stop than the other.

It does not take sophisticated equipment to replicate the test, any kind of electrical gyroscope and a chronometer with one second precision. To get a better idea about the acting forces do it barehanded. Big surprise awaits you.

Nice

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Sorry, Rakesh, but this is not "nice;" it is foolishness.

Let's look at a few quotes from what NonGrata has written.

1) "Very few scientists dare to doubt conservation of energy ..." Wrong!!! Very few folks with any education at all would believe that energy is conserved in all situations. In fact, what we know is that energy is conserved under some conditions, and not conserved when it is not.

2) The quote  from Walker, Halliday, & Resnick, "Energy cannot magically appear or disappear," shows the confusion in the mind of NonGrata. The book authors are speaking of "total energy," while the engineering concept of energy used when engineers speak of "conservation of energy" is mechanical energy, specifically excluding thermal energy. When mechanical energy is converted to thermal energy, there is no direct means of recovery. It can only be recovered by complex processes such as producing steam to pass through a turbine or steam engine.

3) Speaking of gyroscopes, NonGrata says, "RPM is proportional to kinetic energy." Wrong!!! He clearly does not know anything about mechanics. Kinetic energy of rotation is proportion to the square of the RPM.

4) Still speaking of gyroscopes, NonGrata describes a proposed experiment involving two different gyros, or alternatively, two gyros in different situations at the same time. But notice this: He says that in each case, the gyro comes to rest. If he believes in the absolute conservation of energy (with out distinction between mechanical and thermal), where did the energy go when the gyro comes to rest?

5) As a final point, look at the writer's name: NonGrataEngineering. The first part, Non Grata, is Latin meaning "an unwelcome person." Well, he certainly got that part correct! We should not welcome those who spread ignorance, foolishness, and confusion, whether it be deliberate (with the intent to mislead others), or simply through their own ignorance.

DrD

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