Force
A uni-directional load applied to a point or rigid body(newtons)
Stress
An applied normalised by the cross sectional area over which it is applied (Nmm^2, MPa)
Pressure
Very similar to stress, but typically applied to fluids instead of solids
Rigid body mechanics deals with: Statics (3)
Equilibrium of bodies
At rest
Move with constant velocity
Rigid body mechanics deals with: Dynamics (1)
Motion of bodies, involving acceleration
Mechanics can be divided into 3 main branches
Rigid body mechanics
Deformable body mechanics (solid mechanics)
Fluid mechanics