The highest that george can suck water up a very long straw is 2.0 m . (this is a typical value.) what is the lowest pressure that he can maintain in his mouth?

Explanation:

The height of water column of 2 m will require a gauze pressure of mouth equal to negative value of the following.

pressure = hdg  ; h= 2m; d= density of water = 1000 kg/m³ g = 9.8 m/s²

P = 2 x 1000 x 9.8 = .196 x10⁵ Pa

pressure of the mouth = normal pressure of the air in the mouth + negative pressure created by man = (1-.196) x 10⁵ Pa = .804 x 10⁵ Pa