Recent content by david316

I guess it's not going into kinetic energy as the weight lifter so it presumably has to go into potential energy (elastic potential energy of the muscles I guess) and heat?

I'm slowly getting there but would you be able to elaborate? In particular when the weight lifter lowers the weight as I understand it, the force of the weight will do positive work on the weightlifter. So 5000J of energy is transferred from the weight to the weightlifter. Is this correct? If it...

Thanks.

I don't know if a strong person has greater efficiency lifting weights than a weak person so don't know. When lowering the weight if the lifter applies 250N to oppose the 2500N of the weight and assume ideal efficiency of 1.0 how much energy does the lifter use when lowering the weight.

Would there be anyway to work out how much energy the weight lifter uses when lowering the weight?

Ok...I was mixing up work with energy used. I now realize they are not the same thing. Just because the weight lifter does zero work which is clear as the net transfer of energy to the mass is zero that does not mean he uses zero energy in lifting and lowering the weight.

Also, thank you for you time. I do appreciate it.

Ok sure...but I'm struggling to understand why the relationship between work and energy use is a meaningless equivalence. If the weight lifter does 5000J work he must use at least 5000J of energy in lifting the weight. When he lowers the weight he must use greater than 0J of energy in lowering...

Forgive my ignorance but when the weight lifter lifts the weight and does 5000J of work on the weight where does the energy come from to do that 5000J work?

I guess ultimately I am trying to relate the work done as a product of force times distance to the energy used by the weight lifter. For example if I weigh 1000N and do ten pushup of 0.1m each can I say I would have used at least 1000J of energy as 1000N * 0.1m * 10 = 1000J.

So is it fair to say that when he lifts the weight he does 5000J of work plus additional energy of his muscles "applying" the force (i.e. contractions etc similar to using energy when a human pushes against a wall). If we assume this additional energy is negligible I can say he used 5000J...

I guess the way I think about it is that when the weight lifter lifts the weight he uses energy to do so. So the weight lifter has used 5000J of energy in lifting the weight. Presumably from the energy stores in his body. i.e. he burns calories. But when he lowers the weight he does not get the...

Hello, I'm getting a little confused and would appreciate some clarification. If a weight lifter lifts a weight of 2500N a distance of 2m, the work done by the weight lifter's force on the weight is 5000J. The work done by the weight force due to gravity is -5000J. The weight lifter then...

Thanks.

Hello, I am after some help to try and understand SVM implementation is a micro that controls a motor. As I understand it one of the advantages of using space vector modulation over sinusoidal PWM modulation in motor control is that it can control the phase voltages such that the line-to-line...