Question

(a) A vacuum system has a hose 2.68 cm in diameter. With the end of the hose placed perpendicularly on the flat face of a brick, what is the weight (in N) of the heaviest brick that the system can lift?

__________ N

(b) An octopus uses one sucker of diameter 2.68 cm on each of the two shells of a clam in an attempt to pull the shells apart. Find the greatest force (in N) the octopus can exert on a clamshell in salt water 33.8 m deep.

__________ N

Answer 1

Solution:

Part (a) Solution :

atmospheric pressure : P_o = 1 atm =101325 Pa

We have, diameter = 2.68 cm,

Thus: Radius (r) = 1.34 cm = 0.0134 m

Force = P A = (101325)()(0.0134 m)2 = 57.16 N

Part (b) Solution:

Given: r = 1.34 cm ,

density of salt water () =1027 kg/m³,

and, h = 33.8 m

P = Po + g h

P = 101325 + (1027 x 9.8 x 33.8)

P = 441508.48 Pa

Thus : Force = P A = (441508.48)()(0.0134 m)2 = 249.06 N