What is work energy theorem?

1 Answer
Aug 14, 2017

See below.

Explanation:

The work-energy theorem states that an increase in the kinetic energy of a (rigid) body is caused by an equal amount of positive work done on that body as a result of the net force acting on the body and vice versa.

#color(crimson)(DeltaE_"system"=DeltaK+DeltaU+DeltaE_"th"=W)#

  • #W>0" "=># environment does work on the system and the system's energy increases

  • #W<0" "=># system does work on the environment and the system's energy decreases

Much of the time (at least in lower-level physics classes or similar), we deal only with #DeltaU# and #DeltaK#, where the change in energy is a loss due to fiction, so we might commonly see this statement as a result of the theorem:

#color(blue)(W_"friction"=DeltaK+DeltaU)#