An iron sphere of mass `20xx10^(-3)` kg falls througha viscous liquid with terminal velcoity 0.5 `ms^(-1)`. The terminal velocity (in `ms^(-1)`) of another iron sphere of mass `54xx10^(-2)kg ` is

Options

A. 4.5
B. 3.5
C. 2.5
D. 1.5

Answer

A

Explanation

Terminal velocy, `vpropr^(2)`
or `(v_(1))/(v_(2))=((r_(1))/(r_(2)))^(2)=[((r_(1))/(r_(2)))^(3)]^(2//3)`
`implies(v_(1))/(v_(2))=((M_(1))/(M_(2)))^(2//3)`
`therefore(0.5)/(v_(2))=((20xx10^(-3))/(54xx10^(-2)))^(2//3)`
`(0.5)/(v_(2))=(1)/(9)`
`impliesv_(2)=4.5ms^(-1)`.