Chapter 7
1. For a centrifuge of radius 0.07m and rpm 10000, find out centrifugal force developed.
Ans. r=0.07 m
2
2
60
2
0.001118
N
Fc
rN
Fg
π
ω
=
=
=0.001118x0.07)10
8
=7826
F
c
=7826F
g
2. For a centrifuge of radius 0.05m, and rpm of 12000, find out terminal velocity of a
particle of diameter 10 µm and density 1260 Kg/m
3
in an aqueous solution.
Ans
rpm=12000
2 2 12000
1256 /
60 60
N
rad s
π π
ω
×
= = =
2 2
( )
18
rd p
t p
ω
ν ρ ρ
µ
= −
r=0.05m
D
p
=10x0
-6
m;
p
ρ
=1260 kg/m
3
2 10
1256 0.05 10
(1260 1000)
3
18 10
t
ν
−
× ×
= −
−
×
