Available Answers

1. 1.

   A body weighs 200 gf in air and 190 gf when completely immersed in water. Calculate :

   1. the loss in weight or the body in water,
   2. the upthrust on the body.
2. 2.

   A small stone of mass m (= 200 g) is held under water in a tall jar and is allowed to fall as shown in Fig. 5.7. The forces acting on stone are also shown.

                                                  

   1. What does F₂ represent ?
   2. What does m₁ represent ?
   3. What is the net force acting on stone ?
   4. What is the acceleration of Stone as it falls through water? Neglect the force due to viscosity. Assume that the volume of stone = 80 cm³, density of water = 1.0 g cm^-3 and acceleration due to gravity g = 10 m s^-2.
3. 3.

   A piece or iron of density 7.8 x 10³ kg m^-3 and volume 100 is completely immersed in water ( ρ = 1000 kg m^-3). Calculate : (i) the Weight of iron piece in air, (ii) the upthrust, and (iii) its apparent weight in water. (g = 10 m s^-2)

4. 4.

   A metal cube of side 5 cm and density 7.9 g cm^-3 is suspended a thread and is immersed completely in a liquid of density 1.1 g cm^-3  Find : (a) the weight of cube. (b) the upthrust on cube and (c) the tension in thread.

5. 5.

   A solid of density  has weight W. Show that its apparent weight will be W[l - (ρ₁/ρ)]   when it is completely immersed in a liquid of density ρ_1.

6. 6.

   What do you understand by the term upthrust of a fluid ? Describe an experiment to show its existence.