f a 200lb person stands on a weightless piston that is 15ft
     f a 200-lb person stands on a weightless piston that is 1.5-ft in diameter and connected to a small vertical tube, how high will water in the tube rise above the bottom of the piston? wate ft Piston Premure mereo  
  
  Solution
Area of the piston = 3.14 * 1.5*1.5/4 =1.77 ft2
Pressure on piston = 200/1.77 = 113.23 lb/ft2
water rise = pressure/(unit weight of water)
=113.23/62.4
=1.812 ft
If mercury,
height rise = pressure/(unit weight of mercury)
height = 113.23/847
=0.1334 ft
=1.6 inch

