Exam questions on floating and sinking covers varied concepts that determine what makes objects floats or sinks in fluids. Some of the most important concepts includes density, volume and mass.
What Exam Questions on Floating and Sinking Test?
- Understanding of Key Concepts
- Density: Ability to compare densities of objects and liquids to predict floating or sinking.
- Buoyant Force / Upthrust: Understanding how an upward force acts on objects in a fluid.
- Archimedes’ Principle: Knowing that the upward force equals the weight of the fluid displaced.
- Application of Theory
- Predicting whether an object will float, sink, or partially submerge.
- Explaining real-life examples (ships, icebergs, cork, boats).
- Understanding how shape affects flotation, not just material.
- Numerical & Analytical Skills
- Calculating density from mass and volume.
- Determining the fraction of a floating object submerged.
- Using formulas to relate buoyant force, weight, and displaced fluid.
- Observation & Reasoning
- Explaining why certain objects behave differently in water.
- Understanding the effect of changing variables (shape, volume, material).
- Reasoning why an object rises if pushed slightly deeper in a fluid.
- Practical Awareness
- Recognizing applications in real life (boats, ships, hot air balloons).
- Relating theory to experiments (floating block, foil boat, cork in water).
In short: Exam questions test conceptual understanding, problem-solving, reasoning, and practical application of the laws of flotation.
here are some of the questions to test floating and sinking concepts
1. (a) State Archimedes’ principle (1mk)
2. (b) Figure I0 shows a solid cylinder floating between two liquids A and B of densities 0.8g/cm3 and 1.2g/cm3 respectively. Half of its volume sinks in liquid B as shown. The cylinder has a diameter of 7cm and a length of 12cm. uses it to answer questions that follows.
Find;
(i) The volume of the liquid B displaced (2mks)
(ii)Upthrust on the cylinder due to liquid B (3mks)
(iii) Upthrust on the cylinder due to liquid A (3mks)
(iv) The mass of the cylinder (2mks)
Question 2
(a) State the law of floatation. (1 mk)
( b) A balloon of volume 2000m3 is filled with hydrogen of density 0.09Kg/m3. If the mass of the fabric is 100kg and that of the pilot is 75kg, what will be the greatest mass of equipment that can be carried by the balloon when operating in air of density 1.25kg/m3 (4 mks)
Question 3
(ii) Fig. 6 shows a piece of cork held with a light thread attached to the bottom of
a beaker. The beaker is filled with water.
(I) Indicate and label on the diagram the forces acting on the cork. (3 marks)
(II)Write an expression showing the relationship between the forces. (1 mark)
III) If the thread breaks name another force which will act on the cork. (1 mark)
b) A solid displaces 8.5 cm3 of liquid when floating on a certain liquid and 11.5 cm3 when fully submerged in the liquid. The density of the solid is 0.8 gcm3
Determine:
i) The upthrust on the solid when floating. (3 marks)
ii) The density of liquid. (3mrks)
iii) The upthrust on the solid when fully submerged (3marks)
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