Answer: Buoyant force is due to volume of boat and density of water.
Question: 2. what is the cause of buoyant force?
Answer: : The pressure difference on lower part and upper part of a body cause of buoyant force .
Question: 3. An Object of volume V is immersed in a liquid of density P. Calculate the magnitude of buoyant force acting on the object due to the liquid
Answer: Vd g
Question: 4. why does a block of wood held under water rise to the surface when released?
Answer: This happens because as upward force is greater than the weight.
Question: 5. What happens to the buoyant force as more and more volume of a solid object is immersed in a liquid. When does the buoyant force become maximum?
Answer: The buoyant force exerted by a fluid is equal to the weight of fluid displaced. Therefore the buoyant force increases as more and more volume of a solid object is immersed in a liquid.
Question: 6. Explain why, a piece of glass sinks in water but it floats in mercury.
Answer: The density of glass is more than water, but less then mercury, Therefore glass float on mercury and sinks in water.
Question: 7. When is the pressure on the ground more when a man is walking or when a man is standing ? Explain.
Answer : When a man is walking is weight is alternately on one feet or the other, when he is standing, his weight is divided on both feet. Therefore pressure is more on the ground when he is walking (as surface area is less).
Question: 8. A solid weighs 80 g in air, 64 g in water. Calculate the relative density of solid. When kept in water, state if the object would float or sink?
Answer: Weight loss in water = (80 - 64) g = 16
Question: 9. why density varies?
Answer: The density of a material depends on two things.
Question: 10. An object is suspended with a string . The string is stretched. When the object is completely immersed in water, the extension of the thread decreases. Why?
Answer : This happen because when the object is completely immersed in water it experience an upward force that cause weight loss.
IX Thrust and Pressure, Archimedes’ Principle, Relative Density
CBSE Class 9 - Science - Chapter 10: Flotation: Notes and Quest
MCQ: Flotation: Thrust, Pressure, Buoyancy and Density
Thrust and Pressure, Archimedes’ Principle, Relative Density key point
Notes : Flotation: Thrust, Pressure, Buoyancy and Density
Physics Flotation Term-II Class IX Buoyant force Detail Study
9th Physics Solved Numerical Floating bodies