Question

why the direction of the force exerted by water on the surfaces of a cubical body submerged in it is always normal to the surface of the object?

Answer 1

• Pressure: It is the normal force exerted on the unit surface area.
• At any surface inside the liquid, the pressure acting in all directions is same.
• In the case of a body immersed in a liquid, the liquid displaced by the immersed portion try to attain its original space. During this course, it applies an upward force called buoyant force in upward direction. This buoyant force is equal to the weight of the liquid displaced by the immersed portion.
• This buoyant force is caused due to difference in pressure between upper and lower surfaces of the given body. As this buoyant force is applied normally to the surface, it can be concluded that the direction of force exerted by water on the surface of a cubical body is always normal to the surface of the object.