Suction of Vaccum and Octopus?

Question

(a) A very powerful vacuum cleaner has a hose 3.05 cm in diameter. With no nozzle on the hose, what is the weight of the heaviest brick that the cleaner can lift?
N
(b) A very powerful octopus uses one sucker of diameter 3.05 cm on each of the two shells of a clam in an attempt to pull the shells apart. Find the greatest force that the octopus can exert in salt water 32.3 m depth.
N

Answer 1

this is a pressure question, newtons per square cm being the easy units. since you're looking for the 'max' the limiting factor is the air pressure outside the vacuum/ sucker.
In air, standard pressure is 101 kilopascal, or 101,325 Pa, = 101,325N/sq meter or 10.1 N/sq cm
the area of the hose is pi r^2 = pi x 1.5025^2 = 7.3sqcm
so the max force that can be applied is the pressure times the area. and the max mass is that force divided by g.

b) is the same only you need the pressure of water at 32.3m depth.