# NCERT Physics Class 11 Exemplar Ch 10 Mechanical Properties of Fluids Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

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## Very Short Answer

Q. 11 Is viscosity a vector?

Answer: No.

Q. 12 Is surface tension a vector?

Answer: No.

Q. 13 Iceberg floats in water with part of it submerged. What is the fraction of the volume of iceberg submerged if the density of ice is ?

Answer: Let the volume of the iceberg be . The weight of the iceberg is

. If is the fraction submerged, then the volume of water displaced is . The buoyant force is where is the density of water.

Q. 14 A vessel filled with water is kept on a weighing pan and the scale adjusted to zero. block of mass and density is suspended by a massless spring of spring constant k. This block is submerged inside into the water in the vessel. What is the reading of the scale?

Answer: Let x be the compression on the spring. As the block is in equilibrium

where is the density of water and V is the volume of the block. The

reading in the pan is the force applied by the water on the pan i.e.. ,

Since the scale has been adjusted to zero without the block, the new

reading is

Q. 15 A cubical block of density is floating on the surface of water. Out of its height L, fraction is submerged in water. The vessel is in an elevator accelerating upward with acceleration . What is the fraction immersed?

Answer: Let the density of water be

Then

Thus, the fraction of the block submerged is independent of any acceleration, whether gravity or elevator.