A Newtonian fluid fills the clearance between a shaft and a sleeve. When a force of 800 N is applied to the shaft, parallel to the sleeve, the shaft attains a speed of `2 cm s^(-1)`. If a force of 2.4 kN is applied instead, the shaft would move with a speed of

Options

A. `2cms^(-1)`
B. `15cms^(-1)`
C. `6cms^(-1)`
D. None of these

Answer

C

Explanation

Viscous force is given by
`F=eta A v/d`
`(F_(1))/(F_(2))=(v_(1))/(v_(2))`
`800/2400=2/(v_(2))`
`v_(2)=6m//s`