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Fluid Mechanics MCQs - Buoyancy and Floatation
Fluid Mechanics MCQs - Buoyancy and Floatation: This section contains the multiple-choice questions and answers on the fluid mechanics chapter Buoyancy and Floatation. practice these MCQs to learn and enhance the knowledge of Buoyancy and Floatation.
1. Amongst which of the following is related to the buoyant force experienced by an object immersed in a fluid?
- The weight of the object
- The weight of the fluid that the object displaces
- Zero
- The volume of the object
Answer: B) The weight of the fluid that the object displaces
Explanation:
The buoyant force on an object submerged in a fluid is equal to the weight of the fluid that the object has displaced, according to Archimedes' principle. This is why objects that are less dense than the fluid float.
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2. The buoyant force acting on a submerged item in a fluid is equal to ____.
- The volume of the fluid displaced
- The weight of the fluid displaced
- The mass of the fluid displaced
- The density of the fluid
Answer: B) The weight of the fluid displaced
Explanation:
As per Archimedes' principle, the buoyant force acting on an object immersed in a fluid is equal to the weight of the fluid displaced by the object.
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3. The concept of buoyancy and floatation is based on ____.
- Newton's laws of motion
- Pascal's principle
- Bernoulli's equation
- Archimedes' principle
Answer: D) Archimedes' principle
Explanation:
Buoyancy and floatation are governed by Archimedes' principle, which states that the buoyant force on an object immersed in a fluid is equal to the weight of the fluid displaced by the object.
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4. The net force experienced by an object submerged in a fluid is ____.
- Zero
- Upward
- Downward
- Indeterminate
Answer: A) Zero
Explanation:
When an object is in equilibrium (neither sinking nor rising), the net force on it is zero, meaning that the buoyant force and the object's weight are balanced.
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5. Amongst which of the following is the center of buoyancy of an object submerged in a fluid?
- The geometric center of the object
- The point where the buoyant force acts on the object
- The point where the object's weight is concentrated
- The point at which the object will sink
Answer: B) The point where the buoyant force acts on the object
Explanation:
The center of buoyancy is the point within an object immersed in a fluid where the buoyant force is applied, and it coincides with the centroid of the displaced fluid.
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6. How does the center of buoyancy change when an object is fully submerged in a fluid?
- It moves upward
- It moves downward
- It remains at the same location
- It shifts toward the rear of the object
Answer: C) It remains at the same location
Explanation:
When an object is fully submerged, the center of buoyancy coincides with the center of mass of the object, and it remains at the same location.
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7. The center of buoyancy of a symmetrical object completely submerged in a fluid is located at it's ____.
- Geometric center
- Top surface
- Bottom surface
- Front surface
Answer: A) Geometric center
Explanation:
For a symmetrical object fully submerged in a fluid, the center of buoyancy is located at its geometric center.
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8. What type of equilibrium exists when an object is at rest and remains at rest even when subjected to small disturbances?
- Neutral equilibrium
- Stable equilibrium
- Unstable equilibrium
- Dynamic equilibrium
Answer: B) Stable equilibrium
Explanation:
In stable equilibrium, an object returns to its original position after experiencing small disturbances, indicating a tendency to maintain its equilibrium state.
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9. A ball is placed at the bottom of a concave bowl and comes to rest without rolling further. What type of equilibrium does the ball demonstrate?
- Neutral equilibrium
- Stable equilibrium
- Unstable equilibrium
- Dynamic equilibrium
Answer: B) Stable equilibrium
Explanation:
In a stable equilibrium, the ball remains at rest at the bottom of the concave bowl, even if slightly displaced, as it tends to return to its original position.
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10. What type of equilibrium exists when an object is balanced but the slightest disturbance causes it to move away from its original position?
- Neutral equilibrium
- Stable equilibrium
- Unstable equilibrium
- Dynamic equilibrium
Answer: C) Unstable equilibrium
Explanation:
Unstable equilibrium occurs when a small displacement from the balanced position results in the system moving away and not returning to its original position.
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11. A completely submerged body will be stable if ____.
- Its density is lower than that of the fluid
- Its center of gravity is lower than its center of buoyancy
- Its center of gravity is above its center of buoyancy
- Its weight is greater than the buoyant force
Answer: B) Its center of gravity is lower than its center of buoyancy.
Explanation:
A completely submerged body's center of gravity must be lower than its center of buoyancy in order for it to remain stable. This ensures that any small disturbance will result in a restoring torque that brings the body back to its original position.
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12. When a fluid is at rest, the magnitude of the hydrostatic force on a curved surface is ____.
- Zero
- Constant
- Equal to the fluid's weight
- Variable depending on the depth
Answer: C) Equal to the fluid's weight
Explanation:
When a fluid is at rest, the hydrostatic force on a curved surface is equal to the weight of the fluid above the surface, acting downward.
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13. The hydrostatic force on a curved surface increase with ____.
- Decreasing depth of submersion
- Increasing fluid density
- Decreasing surface area
- Increasing surface curvature
Answer: B) Increasing fluid density
Explanation:
The hydrostatic force on a curved surface increases with an increase in fluid density since the force is directly proportional to the fluid density.
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14. What is metacentric height in the context of buoyancy and floatation?
- The distance between the center of buoyancy and the center of gravity of the floating object
- The distance between the center of buoyancy and the water surface
- The distance between the center of gravity and the surface of the water
- The distance between the center of mass and the center of volume of the floating object
Answer: A) The distance between the center of buoyancy and the center of gravity of the floating object
Explanation:
Metacentric height is a measure of the stability of a floating object and is the vertical distance between the center of buoyancy and the center of gravity.
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15. Which factor affects the metacentric height of a floating vessel?
- The shape of the vessel
- The mass of the vessel
- The volume of the vessel
- The density of the fluid
Answer: A) The shape of the vessel
Explanation:
The metacentric height of a floating vessel is influenced by its shape. Vessels with a higher metacentric height are more stable.
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16. The metacentric height of a floating object depends on the ____.
- Material of the object
- Size of the object
- Shape and weight distribution of the object
- Temperature of the fluid
Answer: C) Shape and weight distribution of the object
Explanation:
The metacentric height of a floating object is influenced by its shape and weight distribution. Objects with lower centers of gravity and certain hull shapes tend to have higher metacentric heights, resulting in better stability.
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17. If the metacentric height (GM) of a floating body increases, what will happen to its time period of oscillation?
- Time period will decrease
- Time period will increase
- Time period will remain the same
- Time period depends only on the least radius of gyration
Answer: B) Time period will increase
Explanation:
As per the formula, the time period of oscillation is directly proportional to the square root of the metacentric height (GM). Hence, if the metacentric height increases, the time period of oscillation will also increase, indicating a slower oscillation.
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18. Which factor is responsible for determining the frequency of oscillation in the time period formula?
- Least radius of gyration (k)
- Metacentric height (GM)
- Time period of oscillation (T)
- Acceleration due to gravity (g)
Answer: B) Metacentric height (GM)
Explanation:
The metacentric height (GM) is one of the factors that determine the frequency of oscillation in the time period formula. It represents the distance between the center of buoyancy and the metacenter and influences the stability and oscillation behavior of the floating body.
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19. What does the variable "T" represent in the time period formula for a floating body's oscillation?
- Least radius of gyration
- Metacentric height (GM)
- Time period of oscillation
- Acceleration due to gravity
Answer: C) Time period of oscillation
Explanation:
In the formula, "T" represents the time period of oscillation, which is the time taken for one complete cycle of oscillation of the floating body.
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