Thread: Anyone good in physics? Well I've got a question just for YOU! Please help :)

Originally Posted by Philosopher8659

I would say it is the same for each, simply stop pushing. I do not recall work being defined by the removal of effort.

Work is defined as the amount of energy transfered to a system through forces that act on that system in some distance. Being that all bodies in motion will remain in the same, uniform motion unless external forces are enacted upon them, what do you think causes, say, a crate moving over a flat surface to suddenly slow down? The magical phenomenon at work here (no pun intended) is called friction. This is why you can "simply stop pushing". There is still a force being exerted against the motion of the crate in some distance. Energy is being transferred as kinetic energy to the Earth, and as thermal energy to the contact materials where the crate and ground touch. Differences in velocity are exponentially proportional to the kinetic energy of the system, and differences in mass are directly proportional.

The purpose of the question is to build a fundamental understanding of velocity's relationship to kinetic energy. That is all.

Originally Posted by PhilosopherStoned

Can't you read the title? The question was just for ME!

I see wut you implied thar.

Originally Posted by Invader

Work is defined as the amount of energy transfered to a system through forces that act on that system in some distance. Being that all bodies in motion will remain in the same, uniform motion unless external forces are enacted upon them, what do you think causes, say, a crate moving over a flat surface to suddenly slow down? The magical phenomenon at work here (no pun intended) is called friction. This is why you can "simply stop pushing". There is still a force being exerted against the motion of the crate in some distance. Energy is being transferred as kinetic energy to the Earth, and as thermal energy to the contact materials where the crate and ground touch. Differences in velocity are exponentially proportional to the kinetic energy of the system, and differences in mass are directly proportional.

The purpose of the question is to build a fundamental understanding of velocity's relationship to kinetic energy. That is all.

I think you need to read the physics book again.

Originally Posted by Invader

I see wut you implied thar.

That the title of the thread promised me that because I'm good at physics the question was just for me and made no mention of other people that might be good a physics (or squaring circles)?

Originally Posted by Philosopher8659

This seems to be one of those questions for people who think too much but accomplish too little with it.

Yes. Putting shit in space, airplanes, skyscrapers, cellphones, computers, etc. is "too little". You've made your "point", now please run along.

Originally Posted by Philosopher8659

I think you need to read the physics book again.

I think you need to read the physics book to begin with. And FYI, I'm not talking about Aristotle.

Originally Posted by Philosopher8659

Is work the same as the removal of velocity? Work is always positive.

As defined with Invader's typo, yes it is always positive (so long as v is real). Unfortunately for your assertion, it's a typo.

W = ½m(v₂²-v₁²)

As you can see, this can clearly be negative. It is equivalent to a change in kinetic energy.