First slide

Viscous flow/Laminar flow

Question

A block B of mass 13 kg and base area 1 m x 1m is sliding on an inclined plane lubricated by an oil layer of thickness 0.15 cm. It is observed that block slides with a steady speed of 0.5 m/s. Find viscosity of oil (in Pl). (Take g = 10 m/s²)

Moderate

Solution

Velocity gradient in oil layer
$\frac{dv}{dx} = \frac{v}{x} = \frac{0 .5}{0 .15 \times 10^{- 2}} = \frac{1000}{3} \sec^{- 1}$
for steady speed of block
viscous force on block $F = mgsin θ$
$ηA \frac{dv}{dx} = (13) (10) (\frac{5}{13})$
$η = \frac{50}{1 \times (1000 / 3)} = \frac{15}{100} = 0 .15 Pl$

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