Sorry. I cannot accept your explanation. You eliminate the possibility of using centripetal force as being part of your work output equation by framing your equation in that manner. If you "a priori" exclude centripetal force, then obviously it seems that centripetal force doesn't require energy to become operant. The energy may not be utilised to generate forward momentum (forward kinetic energy) along the race track (in the car example), but energy is required to keep the car on a circular track (and the car's tires know that).
I'm sorry you're sorry you cannot accept my explanation but I assure you it is the one and only technically correct one. First off the force is called tension (axial load)... and it has two components (one in the normal, perpendicular to path i.e. centripetal direction and one in the tangential direction.) The normal component of the tension force does not move the object closer to the center of rotation and therefore it does NO WORK! The tangential component on the other hand accelerated the object along the path. The tangential component (and this is the one thing BerntR and I can agree on) is what does the work.
Originally Posted by Jeff
Consider a simple example.
Imagine traveling in a NYC subway car that is traveling at 40mph on a straight rail track. Imagine that you are standing in the center aisle and holding onto a vertical post. Then imagine what happens when the subway car goes around a tight bend at the same speed. You will have to hang onto that vertical post for "dear life" to prevent yourself from being catapulted down the length of the subway car. It requires "energy" to remain stationary in balance and that energy is the energy required to offset a centrifugal force acting on your body. I would imagine that the subway car also needs to expend energy to stay in balance on its circular track, and that energy is centripetal energy.
Jeff.
NO it does not require energy! It requires a FORCE (see click here->Centripetal force requirement. This is why we have a variety of words in the lexicon: FORCE WORK ENERGY etc. soforth.... They have different meanings. AGAIN.... SOME FORCES DO NO WORK.
If you are hanging motionless on a jungle gym there is a force in your arms .... but you're not doing work... you're not expending power... You're hanging there motionless. You don't do work until you do a pull up. When you do a pull-up you are moving that force (mass X gravity) through a distance ... THAT is work... THE requires Hp. Hanging Motionless does not..... but there is a FORCE present when you hang motionless... make no mistake about that!
I'm done with this one.... believe what you want to.... makes no difference to me really.... Merry Christmas Jeff
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