A 15 cm radius air duct is used to replenish
the air of a room 10. m x 5.0 m x 4.5 m every 10. minutes. How fast
does the air flow in the duct? Physics Charts - Densities of Substances
2.
A 1.00 cm inside diameter garden hose is
used to fill a round swimming pool 7.20 m in diameter. How long will
it take to fill the pool to a depth of 1.25 m if water issues from the
hose at a speed of 0.0333 m/s? Physics Charts - Densities of Substances
3.
The radius of the aorta is 1.0 cm and the
blood flowing through it has a speed of 30. cm/s. Calculate the
average speed of blood in the capillaries given that, although each
capillary has a diameter of 8 x 10 -4 cm, the total cross
section is about 2000 cm2. Physics Charts - Densities of Substances
4.
How large must a heating duct be if air
moving 3.0 m/s along it can replenish the air every 15 minutes in a room
of 300 m3? Assume the air density remains
constant. Physics Charts - Densities of Substances
A 15 cm radius air duct is used
to replenish the air of a room 10. m x 5.0 m x 4.5 m every 10.
minutes. How fast does the air flow in the
duct? Physics Charts - Densities of Substances
m = V
= 1.29 kg/m3 x 10.m x 5.0 m x 4.5 m
= 290 kg
/\m
----- = Av
Solve for v. /\t
/\m
290 kg
v = -------- =
---------------------------------------------------- = 21 m/s A/\t
1.29 kg m -3 x ( 0.075
m ) 2 x 600 s
2.
A 1.00 cm inside diameter garden
hose is used to fill a round swimming pool 7.20 m in diameter. How
long will it take to fill the pool to a depth of 1.25 m if water issues
from the hose at a speed of 0.333 m/s? Physics Charts - Densities of Substances
/\m = V
/\m
V
V
----- = Av
= --------- => Av
= -------
Solve for /\t. /\t
/\t
/\t
V r2h
h
( 3.60 m )2 x 1.25 m /\t = ------ = ---------- = ----
= -------------------------------------------- = 1.9 x
10 6 s or 22 days
Av r2v
v
( 0.00500 m )2 x 0.333 m s -1
3.
The radius of the aorta is 1.0
cm and the blood flowing through it has a speed of 30. cm/s.
Calculate the average speed of blood in the capillaries given that,
although each capillary has a diameter of 8 x 10 -4 cm,
the total cross section is about 2000 cm2.
Physics Charts - Densities of Substances
Aava = Acvc
Solve for vc.
Aava ( 0.50 cm )2
x 30. cm/s
vc = --------- =
--------------------------------------- = 0.012 cm/s
Ac
2000 cm2
4.
How large must a heating duct be
if air moving 3.0 m/s along it can replenish the air every 15 minutes in a
room of 300 m3? Assume the air density remains
constant. Physics Charts - Densities of Substances
m = V
= 1.29 kg/m3 x 300 m3 = 387
kg
/\m
----- = Av
Solve for A. /\t
/\m
387 kg
A = --------- =
--------------------------------------------- = 0.111 m3 v
/\t 1.29 kg/m3
x 3.0 m s -1 x 900 s
/\V
V
= 1.29 kg/m3 x 10.m x 5.0 m x 4.5 m
= 290 kg
( 0.075
m ) 2 x 600 s