Simplify the following text for a Grade 9 native English-speaking person.
Original: Fluid mechanics can be divided into fluid kinematics , the study of fluid motion , and fluid dynamics , the study of the effect of forces on fluid motion , which can further be divided into fluid statics , the study of fluids at rest , and fluid kinetics , the study of fluids in motion .
Simplified: Fluid mechanics can be divided into fluid statics , the study of fluids at rest , and fluid dynamics , the study of fluids in motion .