At `20.`C, to attain the terminal velocity how fast willan aluminium sphre of radii 1 mm fall though water. Assume flow to be laminar flow and specific gravity (AI) `=2.7eta_("water")=8xx10^(-4) Pa`

Options

A. 9.2 m/s
B. 6.1 m/s
C. 4.6 m/s
D. 2.3 m/s \

Answer

C

Explanation

Terminal velocity
` v_(T) = 2/9 (r^(2)(p - omega)g)/z`
`v_(T) = (2xx (10^(-3))xx (2.7 xx 10^(3) xx 9.8))/(9 xx 8xx10^(-4))`
= 4.6 m/s