Final answer:
Fluid pressure is a scalar quantity, but the forces due to pressure are always exerted perpendicular to any surface because fluids cannot withstand or exert shearing forces.
Step-by-step explanation:
Fluid pressure has no direction, being a scalar quantity, whereas the forces due to pressure have well-defined directions: They are always exerted perpendicular to any surface. The reason is that fluids cannot withstand or exert shearing forces. Thus, in a static fluid enclosed in a tank, the force exerted on the walls of the tank is exerted perpendicular to the inside surface. Likewise, pressure is exerted perpendicular to the surfaces of any object within the fluid.
Fluid pressure having no direction is caused by fluids not being able to withstand or exert shearing forces. Thus, the forces due to pressure are always exerted perpendicular to any surface. This is true for static fluids in tanks, as well as for objects within the fluid. The perpendicular force is a result of the inability of fluids to withstand or exert shearing forces.
The direction of the force exerted by static fluids being perpendicular to surfaces is directly related to the nature of fluids. Fluid pressure, being a scalar quantity, has no direction. However, the forces due to pressure are well-defined and are always exerted perpendicular to any surface. This is because fluids cannot withstand or exert shearing forces, resulting in pressure being exerted perpendicular to all surfaces within the fluid.