A boy set up an experiment as shown in the diagram. As he slides the magnet across the wooden board, the ball bearing followed the magnet's movement and direction. What does the experiment show?

(i) Magnetic force can be seen due to friction between ball bearing and wooden board.
(ii) Friction and gravity help to move the ball bearing.
(iii) The ball bearing is made of a magnetic substance.
(iv) Magnetic force can pass through the wooden board.

The given figures show the forces required to move a $100 \mathrm{g}$ object over different surfaces. The friction is greatest at

A block of mass $10 \mathrm{kg}$ is suspended through two light spring balances as shown in figure. Then:

(Neglect the mass of spring balance)

Three identical vessels $A, B$ and $C$ contain same quantity of liquid. In each vessel, blocks with different densities but same masses are placed as shown in figure. If $F_A, F_B$ and $F_C$ are the total forces acting on the base of vessels $A, B$ and $C$ respectively, then