Question

cancel all alarm in 20 degree celsius has questioned the viscosity 2.43 Newton per metre square and a density of 940 kg per metre cube determine the time taken for the steel ball to fall at 2m​

Answer 1

Explanation:

Correct option is

A

5cms

−1

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

, So we have

V

1

V

2

=(

r

1

r

2

)

2

V

2

=(

2

1

)

2

V

1

=

4

20

m/s=5m/s