Answer:
0.86 m/s
Explanation:
A = cross-sectional area of the duct = 900 cm² = 900 x 10⁻⁴ m²
v = speed of air in the duct
t = time period of circulation = 40 min = 40 x 60 sec = 2400 sec
V = Volume of the air in the room = volume of room = 7 x 11 x 2.4 = 184.8 m³
Volume of air in the room is given as
V = A v t
inserting the values
184.8 = (900 x 10⁻⁴) (2400) v
v = 0.86 m/s
