A force of 50 kgf is applied to the smaller piston of a hydraulic machine. Neglecting friction, find the force exerted on the large piston, if the diameters of the pistons are 5 cm and 25 cm respectively.

Two cylindrical vessels fitted with pistons A and B of area of cross section 8 cm ² and 320 cm ² respectively, are joined at their bottom by a tube and they are completely filled with water. When a mass of 4 kg is placed on piston A, find : (i) the pressure on piston A, (ii) the pressure on piston B, and (iii) the thrust on piston B.

Assertion (A) : A brick exerts maximum pressure on ground when it is placed with its longest side vertical.

Reason (R) : Larger the area on which a given thrust acts, lesser is the pressure exerted by it.

1. both A and R are true and R is the correct explanation of A
2. both A and R are true and R is not the correct explanation of A
3. assertion is false but reason is true
4. assertion is true but reason is false

Assertion (A) : The walls of a dam are made thicker at the bottom.

Reason (R) : Pressure is the same in all directions about a point inside the liquid.

1. both A and R are true and R is the correct explanation of A
2. both A and R are true and R is not the correct explanation of A
3. assertion is false but reason is true
4. assertion is true but reason is false