The theorem of
conservation of mechanical energy states that the work carried
out on a body is invested exactly in increasing some type of energy.
When a there are only conservative forces in a system: the mechanical
energy remains constant. The kinetic energy is transformed into
potential energy and vice versa. You can see this by clicking here.
When non-conservative forces act on a body, like those of friction, the
mechanical energy no longer remains constant.
The variation in the mechanical energy is precisely the work carried
out by the non-conservative forces.
DE
mechanical = W carried out by the non-conservative forces
The following visual simulates a moving train, you can
vary the motor force on the locomotive (click on and
drag the point of the arrow), you can also vary the mass of the
locomotive and the forces of friction. The idea is that you verify the
principle above, following these steps:
1. Choose the
following initial parameters in the visual: coefficient of
friction=0.1; mass=920 kg; external force =5000 N.
2. With the data from table F, calculate the work carried out
3. Check your results, choosing the same parameters as in step 1 again,
click on "W Tables" and start the animation.
