The area of cross section of the wider tube shown in figure (13-E2) is 900 cm2. If the boy standing on the piston weighs 45 kg, find the difference in the levels of water in the two tubes.


The pressure difference is created due to the weight of the boy on the piston.


Therefore, the pressure is given by,


Here, forces,


where, m is the mass of the boy and g is the acceleration due to gravity.


Area,


—————(1)


We know that pressure is also given by, , —————(2)


where is the density of the fluid and is the height difference.


For water,


Equating (1) and (2)



(ANS)


1