A spherical ball of density `rho` and radius` 0.003m` is dropped into a tube containing a viscous fluid up to the 0 cm mark as shown in the figure. Viscosity of the fluid `=1.26N-s//m^(2)` and its density `rho_(L)=(rho)/(2)=1260kg//m^(3)`. Assume that the ball reaches a terminal speed at 10cm mark. The time taken by the ball to travel the distance between the 10cm and 20cm mark is `(g=10m//s^(2))`

Answer

5s

Explanation

`{:(,V_(T)=(2)/(9)xx(r^(2)(rho-rho_(L))g)/(eta),impliesV_(T)=(2)/(9)xx((3xx10^(-3))^(2)xx1260xx9.8)/(1.260)),(,V_(T)=2xx10^(-2)m//s,impliesV_(T)=2cm//s),(,t=(10cm)/(V_(T)),impliest=5sec):}`