... and grid spacings play an important role in the modelling of dynamical processes in fluids 3.7 Forces 27 3.7 Forces 3.7.1 What Forces Do A non-zero force operates to change the speed and/or the ... vector components of a force of certain magnitude and direction For example, (0, 0, −9.81 m/s2 ) is a force operating into the negative z-direction (downward) With two forces involved, the latter ... the absence of forces If there is a force, on the other hand, there will be a certain change in motion This is known as Newton’s second law of motion 3.7.3 Apparent Forces Apparent forces come into...