Question

A sphere of brass released in a long liquid column attains a terminal speed ${\upsilon }_0$ . If the terminal speed attained by the sphere of marble of the same radius and released in the same liquid is $n{\upsilon }_0$, then the value of n will be. [ Given: The specific gravities of brass, marble and the liquid are 8.5,2.5 and 0.8 respectively.]

• A. $\frac{5}{17}$
• B. $\frac{17}{77}$
• C. $\frac{11}{31}$
• D. $\frac{17}{5}$

Answer 1

The correct option is B $\frac{17}{77}$

$v_0=\frac{2}{g}{r}^2\frac{(8.5-0.8)}{\eta }andn{v}_0=\frac{2}{g}{r}^2\frac{(2.5-0.8)}{\eta }\Rightarrow n=\frac{17}{77}$