A spherical ball of iron of radius 2 mm is falling through a column of glycerine. If densities of glycerine and iron are respectively 1.3 × 103 kg / m 3 and 8 × 103 kg / m 3. η for glycerine =0.83 Nm -2 sec, then the terminal velocity is

Question

A spherical ball of iron of radius 2 mm is falling through a column of glycerine. If densities of glycerine and iron are respectively 1.3 × 103 kg / m 3 and 8 × 103 kg / m 3. η for glycerine =0.83 Nm -2 sec, then the terminal velocity is (A) 0.7 m / s (B) 0.07 m / s (C) 0.007 m / s (D) 0.0007 m / s

Tardigrade Admin · Accepted Answer

Terminal velocity, v 0=(2 r 2(ρ-ρ0) g /9 η) =(2 ×(2 × 10-3)2 ×(8-1.3) × 103 × 9.8/9 × 0.83)=0.07 ms -1

Q. A spherical ball of iron of radius $2 mm$ is falling through a column of glycerine. If densities of glycerine and iron are respectively $1.3 \times 1 0^{3} k g / m^{3}$ and $8 \times 1 0^{3} k g / m^{3}$ . $η$ for glycerine $= 0.83 N m^{- 2} sec$ , then the terminal velocity is

$0.7 m / s$

$0.07 m / s$

$0.007 m / s$

$0.0007 m / s$

Terminal velocity, $v_{0} = \frac{2 r ^{2} ( ρ - ρ _{0} ) g}{9 η}$
$= \frac{2 \times ( 2 \times 1 0 ^{- 3} ) ^{2} \times ( 8 - 1.3 ) \times 1 0 ^{3} \times 9.8}{9 \times 0.83} = 0.07 m s^{- 1}$

Q. A spherical ball of iron of radius 2mm is falling through a column of glycerine. If densities of glycerine and iron are respectively 1.3×103kg/m3 and 8×103kg/m3. η for glycerine =0.83Nm−2sec, then the terminal velocity is

0.7m/s

0.07m/s

0.007m/s

0.0007m/s