4.9 Resistances in Parallel
115
Then, Q A < Q B .
Exercise 4.10 The figure corresponds to the vertical cross section of an underground
mine.
The resistances of airways 1–6 are:
Element
Resistance
N s 2
m 8
1
20
2
15
3
35
4
30
5
18
6
27
Calculate:
(a) The equivalent resistance of the mine.
(b) The loss of pressure between the mouths of the downcast and upcast shafts if
an airflow of 150 m
3 s
−1 is registered in airways 1 and 6.
(c) Comment if the results obtained are possible in a real mine.
Solution
(a) First, the network can be represented schematically in terms of a circuit with
resistances 1–6, thus:
115
Then, Q A < Q B .
Exercise 4.10 The figure corresponds to the vertical cross section of an underground
mine.
The resistances of airways 1–6 are:
Element
Resistance
N s 2
m 8
1
20
2
15
3
35
4
30
5
18
6
27
Calculate:
(a) The equivalent resistance of the mine.
(b) The loss of pressure between the mouths of the downcast and upcast shafts if
an airflow of 150 m
3 s
−1 is registered in airways 1 and 6.
(c) Comment if the results obtained are possible in a real mine.
Solution
(a) First, the network can be represented schematically in terms of a circuit with
resistances 1–6, thus: