# Mystical field

**Classical Mechanics**Level 4

Imagine a point mass moving through a universe where there are no electric or magnetic fields, and thereby no electric or magnetic forces. There is, however, an unknown "mystical force" that is everywhere. As the point mass moves its mass starts evaporating at a rate of \(r = 1~\mbox{g/s}\). However it maintains a constant velocity of \(V = 5~\mbox{m/s}\). You observe the point mass at a point A and \(10~\mbox{s}\) later you observe it at a point B. What magnitude of work **in Joules** did the mystical force do on the point mass between the points B and A?