Question

A steel ball of mass 'm' falls in a viscous liquid
with a terminal velocity 4 ms. If another steel
ball of mass '8 m' falls through the same liquid
then its terminal velocity is
2) 8 ms. 3) 16 ms 4) 2 ms-
1) 4 ms-1​

Answer 1

Answer:

The terminal velocity V of the body of radius r, density ρ falling through a medium of density ρ

o

is given by

V=

9η

2r

2

(ρ−ρ

o

)g

where η is the coefficient of viscosity of medium.

clearly V∝r

2

⇒V∝(volume)

2/3

⇒V∝(m)

2/3

⇒

V

1

V

2

=(

m

1

m

2

)

2/3

⇒

V

V

2

=(

m

8m

)

2/3

⇒V

2

=4V