Work done by (non)conservative force?

Question

In the following question, the answer is a
http://tinyurl.com/2musg7

My understanding is,
amount of work done of conservative force
=amount of decrease of potential energy
=amount of increase in kinetic energy

decreases of word done of nonconservative force
=decreases of mechanical energy of the entire system

Am I correct?

Answer 1

that is true.
A simple way to Understand this is in terms of mass loss as work is being done. An equivalent mass loss is equivalent to an increase in motional energy. This is assuming that the forces are moving in the same gravity field.