Test: Upthrust In Fluids, Archimedes` Principle And Floatation - Class 9 MCQ

When a submerged object is pushed deeper into a fluid, the buoyant force increases. This is due to the increase in pressure at greater depths, which results in a greater upward force acting on the submerged object. This principle is essential for understanding why certain objects float or sink depending on their depth in the fluid.

A solid object with a density greater than that of water will sink when placed in water. This is because the weight of the object exceeds the buoyant force provided by the displaced water, leading to a net downward force. This principle is commonly observed with metals and other dense materials.

An object will sink in water when its weight is greater than the buoyant force acting on it. This situation occurs because the upward force of buoyancy cannot counteract the downward gravitational force, resulting in the object sinking. This principle can be observed with denser materials that displace less water relative to their weight.

For an object to float, the weight of the object must be equal to the buoyant force acting on it. This balance allows the object to maintain its position in the fluid without sinking or rising, adhering to the principle of floatation.

When an object is floating in equilibrium, the buoyant force acting on it equals the weight of the object. This balance of forces allows the object to float without rising or sinking. This principle is a key aspect of Archimedes' principle and is fundamental in fluid dynamics.

When a cork floats with two-thirds of its volume submerged, it indicates that the buoyant force equals the weight of the cork. This balance allows the cork to float in equilibrium, demonstrating the principle of floatation where the weight of the fluid displaced by the submerged part of the cork is equal to the weight of the cork itself.

The upthrust experienced by an object submerged in a fluid is affected by the fluid's density. A denser fluid exerts a greater buoyant force on the object, increasing the upthrust. This principle is essential in applications such as designing submarines and understanding how various objects behave in different fluids.

The center of buoyancy for a submerged object is always located above the center of gravity for a floating object. This positioning contributes to the stability of the object in the fluid. If the center of buoyancy is below the center of gravity, it helps maintain equilibrium and prevents the object from tipping over.

The relationship between density and floatation is such that the lesser the density of an object compared to the fluid, the easier it floats. If an object's density is less than that of the fluid, it will displace enough fluid to generate a buoyant force that can support its weight, allowing it to float.

The property that allows a person to float more easily in the Dead Sea compared to a regular lake is the density of the fluid. The Dead Sea has a much higher salt concentration, increasing its density. This greater buoyancy makes it easier for individuals to float, as the buoyant force exceeds their weight more significantly than in less dense water.

A hydrogen-filled balloon rises in air due to Archimedes' Principle, which states that an object will float if the buoyant force acting on it is greater than its weight. In this case, the weight of the air displaced by the balloon is greater than the weight of the balloon itself, allowing it to rise.

The principle of floatation applies to large ships compared to small objects like nails because ships have a greater volume and can displace more water, which generates a larger buoyant force. Although ships are made of materials that are denser than water, their design allows them to float due to the significant volume of water they displace, balancing their weight.

The net upward force (upthrust) on a submerged object is caused by the pressure difference between the top and bottom surfaces of the object. The pressure at the deeper surface of the object is greater than that at the shallower surface, resulting in a net upward force that acts to lift the object.

Temperature generally affects the density of most substances by decreasing their density when heated. As substances expand upon heating, their mass remains constant while their volume increases, leading to a lower density. This principle is important in various scientific and engineering applications, including thermodynamics and fluid mechanics.

The principle behind determining the relative density of a solid using Archimedes' principle involves calculating the weight of the solid in air divided by the loss of weight when submerged in water. This method allows for the comparison of the solid's density to that of water, providing a straightforward means to assess buoyancy and material properties.

The apparent weight of an object decreases when it is submerged in a fluid due to the upthrust acting on it. The buoyant force reduces the effective weight of the object, making it feel lighter in water than in air. This concept is crucial for understanding why objects can be more easily lifted in water.

The unit of buoyant force is the Newton (N). This is the standard unit of force in the International System of Units (SI). Buoyant force is calculated based on the volume of fluid displaced and the density of the fluid, following the equation \(F_B = V \cdot \rho \cdot g\).

The relationship between the volume of the submerged part of an object and the density of the fluid in which it is floating is directly proportional. The more dense the fluid, the smaller the volume of fluid that needs to be displaced to support the object's weight, which is crucial in understanding floatation principles.

The upward force acting on a body immersed in a fluid is known as the buoyant force or upthrust. This force is responsible for making objects float or sink in fluids. It arises due to differences in pressure exerted by the fluid on different parts of the submerged object. Understanding buoyancy is crucial in various applications, from designing ships to understanding how swimmers float.

The amount of buoyant force acting on an object submerged in a fluid is determined by the volume of fluid displaced by the object. According to Archimedes' principle, the buoyant force is equal to the weight of the fluid displaced, which depends directly on the submerged volume of the object.