finding energy via integration
Hello, I havnt done physics in quite a while and I just want to ask a question about basic energy that i know how to deal with in algebraic terms, but not through means of calculus. I also don't really get the theory of the equation [itex]E=FD[/itex], where E=energy, F=force, and D=distance
is the F the force it took to move the body distance D? So, for example, applying a force of 20N on a body moves it 4m, [itex]E=FD=(20N)(4m)=80J[/itex]?
if thats the case then how can we express this with derivatives or integrals?