InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
A spherical ball of radius `3.0xx10^(-4) m` and density `10^(4) kg//m^(3)` falls freely under gravity through a distance h before entering a tank of water. If after entering the water the velocity of the ball does not change, find h. Viscosity of water is `9.8xx10^(6) N-s//m^(2)`. |
|
Answer» Correct Answer - A::C Before entering the water the velocity of ball is `sqrt(2g)`. If after entering the water this velocity does not change then this value should be equal to the terminal velocity. Therefore, `sqrt(2gh)=2/9 (r^(2)(rho-sigma)g)/(eta)` `:. h={(2)/(9) (r^(2)(rho-sigma)g)/(eta)}^(2)` `=(2)/(81) xx(r^(4)(rho-sigma)^(2)g)/(eta^(2))` `=(2)/(81)xx((3xx10^(-4))^(4)(10^(4)-10^(3))^(2)xx9.8)/(9.8xx10^(-6))^(2)` `=1.65xx10^(3)m`. |
|