Pressure And Properties of Matter - SS1 Physics Past Questions and Answers - page 3

Archimedes' principle states that when an object is immersed in a fluid, it experiences an upward force known as buoyant force, which is equal to the weight of the fluid displaced by the object. This principle is based on the concept that the pressure exerted by a fluid increases with depth. The buoyant force acts in the opposite direction to the gravitational force, causing objects to feel lighter in a fluid. This principle helps explain why objects float or sink in different fluids and provide the foundation for understanding buoyancy.

The buoyant force acting on an object submerged in a fluid depends on several factors. Firstly, it is directly proportional to the volume of the fluid displaced by the object. The greater the volume of the fluid displaced, the greater the buoyant force.

Secondly, the density of the fluid also affects the buoyant force. If the fluid is denser than the object, the object will float as the buoyant force exceeds its weight. On the other hand, if the object is denser than the fluid, it will sink as the buoyant force is less than its weight. Lastly, the shape and orientation of the object also impact the buoyant force. Objects with larger surface areas experience greater buoyant forces.

Density is a measure of how much mass is packed into a given volume of a substance. It is calculated by dividing the mass of an object by its volume. Mathematically, density = mass/volume. For example, if we have two objects with the same volume but different masses, the one with the higher mass will have a higher density.

Specific gravity is a dimensionless quantity that compares the density of a substance to the density of a reference substance, usually water. It is calculated by dividing the density of the substance by the density of water. Specific gravity is useful in determining the relative density of a substance and comparing it to the density of water. If the specific gravity of a substance is less than 1, it means that the substance is less dense than water and will float on its surface. If the specific gravity is greater than 1, the substance is denser than water and will sink.