First slide

Viscosity

Question

A thin spherical metallic shell of radius R is falling in a viscous fluid. The terminal velocity attained by the falling object will be proportional to [Thickness of the shell remains constant]

Moderate

A

R
B

$R^{2}$
C

1/R
D

$R^{3}$

Solution

Mg = Viscous drag ( $F_{D}$ )
If ‘ $σ$ ’ be the surface density of mass of the shell, then $M = 4 {πR}^{2} σ$
$\begin{array}{l} ∴ 4 {πR}^{2} σ . g = 6 πηR . V_{T} \\ \Rightarrow V_{T} = (\frac{2 σg}{3 η}) R \Rightarrow V_{T} \propto R \end{array}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App