- #1
MechaMZ
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Homework Statement
May i know how do i compute an energy conservative equation for the scenario below, which i don't understand.
If a book is lifted up by a force in order to make it moving upward with a constant velocity.
For conservation of total energy, W1-2 = U1-U2 = K2 - K1
If the object is moving in a constant velocity, isn't K2 - K1 = 0
However, U1 is not equal to U2.
It seems not correct obviously, hope someone could enlighten me.
I guess W1-2 = U1-U2 = K2 - K1 is only valid for isolated system, which should be a system without any external force involves except gravitational force.
I'm very confuse now, hope someone could help me.