Work and Energy

the_emi_guy

Exactly!

I am just realizing that we have a sign error here, perhaps this was the source of your confusion.

It should be 1/2mv^2 + mgh = constant right? Sorry I did not notice this before.

benrocks1

thanks so much for your all your help and time!

CWatters

ONLY for certain problems.

Consider a pendulum swinging back and forth with no air resistance or friction.

At the top of the swing:

PE = Maximum = mgh_max where h is measured from the bottom of the swing
KE = Zero because it stops momentarily

At the bottom of the swing:

PE = Zero
KE = Maximium (= 0.5mV^2)

At any point in between:

PE + KE = Constant = mgh_max

the_emi_guy

Went back and corrected sign error in my posts (don't want to confuse anyone coming along later).

Can't believe I can post so many times and not notice this, what I get for being half asleep I guess