If a 200lb person stands on a weightless piston that is 15ft

If 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?

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