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Re: Swartz letter in AJP (work-energy theorem)



I've been following this thread and have read Swartz's
article. I'm frustrated because I don't really see the need
for the deep analysis that I see being put into this
question.

The so-called "Work-Kinetic Energy Theorem" is simply the
result of combining the kinematic equation

a*x =( vf^2)/2 -(vi^2)/2

and Newton's 2nd Law

F_net = m*a

which gives

F_net * x = 1/2 m vf^2 - 1/2 m vi^2.

Now if you want to stand on your head and say a prayer to
the Sun God that "The Net Work done is numerically equal to
the change in Kinetic Energy", I guess your welcome to do
it, but in fact the equation is simply an application of
basic kinematics and Newton's Laws.

Energy is a wonderful shortcut to solving problems through
the use of scalars instead of vectors - but it's not an
object of worship.

Bob at PC