Mechanical Properties Of Fluids Question 1
Question 1 - 24 January - Shift 2
A Spherical ball of radius $1 mm$ and density $10.5 g / cc$ is dropped in glycerine of coefficient of viscosity 9.8 poise and density $1.5 g / cc$. Viscous force on the ball when it attains constant velocity is $3696 \times 10^{-x} N$. The value of $x$ is
(Given, $g=9.8 m / s^{2}$ and $\pi=\frac{22}{7}$ )
Show Answer
Answer: (7)
Solution:
Formula: Terminal velocity
When the ball attain terminal velocity
$F_v=(mg-F_B)(\because a=0)$
$=V \sigma_b g-V \rho _{\ell} g$
$=Vg(\sigma_b-\rho _{\ell})$
$=\frac{4}{3} \pi(10^{-3})^{3} \times 9.8(10.5-1.5) \times 10^{3}$
$=3696 \times 10^{-7} N$
So, $x=7$
