The magnitude of F is directly proportional to the magnitude of X. It is when the harmonic simple harmonic motion undergo. In physics simple harmonic motion is the motion where restoring force is directly proportional to the displacements. The direction is also opposite to the displacement.
Remember that the total
velocity of the motion is the vector sum of the velocity you would have in
still water and the stream. Always place the vectors carefully to be able to
come up with an accurate sum vector.
