A room has a volume of 120 m^3. An air-conditioning system is used to replace the air in the room every twenty minutes, using ducts that have a square cross ection. Assuming that air can be treated as an incompressible fluid, calculate the length of a side of the square if the air speed within the ducts is 3.0m/s and 5.0m/s.

Question

A room has a volume of 120 m^3. An air-conditioning system is used to replace the air in the room every twenty minutes, using ducts that have a square cross ection. Assuming that air can be treated as an incompressible fluid, calculate the length of a side of the square if the air speed within the ducts is 3.0m/s and 5.0m/s. 
Please and thank you.

Dhruv · Accepted Answer

Use the formula V=Avt
a)120m^3=A(3.0m/s)(1200s)
solve for A
and take the square root of the result will give you 0.18m
b)12m^3=A(5.0m/s)(1200s)
solve for A
and take the square root of the result
will give you 0.14m