Viscocity
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361404 A rain drop of radius \(0.3\;mm\) has a terminal velocity in air \(1\;m{s^{ - 1}}.\) The viscosity of air is \(18 \times 10^{-5}\) poise. Find the viscous force on the rain drops.

1 \(2.05 \times {10^{ - 7}}\;N\)
2 \(1.018 \times {10^{ - 7}}\;N\)
3 \(1.05 \times {10^{ - 7}}\;N\)
4 \(2.058 \times {10^{ - 7}}\;N\)
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361405 Spherical balls of radius ' \(R\) ' are falling in a viscous fluid of viscosity ' \(\eta\) ' with a velocity ' \(v\) '. The retarding viscous force acting on the spherical ball is

1 Inversely proportional to both radius ' \(R\) ' and velocity ' \(v\) '
2 Directly proportional to both radius ' \(R\) ' and velocity ' \(v\) '
3 Directly proportional to ' \(R\) ' but inversely proportional to ' \(v\) '
4 Inversely proportional to ' \(R\) ' but Directly proportional to velocity ' \(v\) '
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361406 When a ball is released from rest in a very long column of viscous liquid, its downward acceleration is ' \(a\) ' (just after release). Then its acceleration when it has acquired two third of the maximum velocity:

1 \(\dfrac{a}{3}\)
2 \(\dfrac{2 a}{3}\)
3 \(\dfrac{a}{6}\)
4 None of these
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361407 Eight drops of water, each of radius \(2\;mm\) are falling through air at a terminal velocity of \(8\;cm\;{s^{ - 1}}\). If they coalesce to form a single drop, then the terminal velocity of combined drop will be

1 \(30\;cm\;{s^{ - 1}}\)
2 \(28\;cm\;{s^{ - 1}}\)
3 \(24\;\,cm\;{s^{ - 1}}\)
4 \(32\;\,cm\;{s^{ - 1}}\)
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361404 A rain drop of radius \(0.3\;mm\) has a terminal velocity in air \(1\;m{s^{ - 1}}.\) The viscosity of air is \(18 \times 10^{-5}\) poise. Find the viscous force on the rain drops.

1 \(2.05 \times {10^{ - 7}}\;N\)
2 \(1.018 \times {10^{ - 7}}\;N\)
3 \(1.05 \times {10^{ - 7}}\;N\)
4 \(2.058 \times {10^{ - 7}}\;N\)
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361405 Spherical balls of radius ' \(R\) ' are falling in a viscous fluid of viscosity ' \(\eta\) ' with a velocity ' \(v\) '. The retarding viscous force acting on the spherical ball is

1 Inversely proportional to both radius ' \(R\) ' and velocity ' \(v\) '
2 Directly proportional to both radius ' \(R\) ' and velocity ' \(v\) '
3 Directly proportional to ' \(R\) ' but inversely proportional to ' \(v\) '
4 Inversely proportional to ' \(R\) ' but Directly proportional to velocity ' \(v\) '
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361406 When a ball is released from rest in a very long column of viscous liquid, its downward acceleration is ' \(a\) ' (just after release). Then its acceleration when it has acquired two third of the maximum velocity:

1 \(\dfrac{a}{3}\)
2 \(\dfrac{2 a}{3}\)
3 \(\dfrac{a}{6}\)
4 None of these
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361407 Eight drops of water, each of radius \(2\;mm\) are falling through air at a terminal velocity of \(8\;cm\;{s^{ - 1}}\). If they coalesce to form a single drop, then the terminal velocity of combined drop will be

1 \(30\;cm\;{s^{ - 1}}\)
2 \(28\;cm\;{s^{ - 1}}\)
3 \(24\;\,cm\;{s^{ - 1}}\)
4 \(32\;\,cm\;{s^{ - 1}}\)
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361404 A rain drop of radius \(0.3\;mm\) has a terminal velocity in air \(1\;m{s^{ - 1}}.\) The viscosity of air is \(18 \times 10^{-5}\) poise. Find the viscous force on the rain drops.

1 \(2.05 \times {10^{ - 7}}\;N\)
2 \(1.018 \times {10^{ - 7}}\;N\)
3 \(1.05 \times {10^{ - 7}}\;N\)
4 \(2.058 \times {10^{ - 7}}\;N\)
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361405 Spherical balls of radius ' \(R\) ' are falling in a viscous fluid of viscosity ' \(\eta\) ' with a velocity ' \(v\) '. The retarding viscous force acting on the spherical ball is

1 Inversely proportional to both radius ' \(R\) ' and velocity ' \(v\) '
2 Directly proportional to both radius ' \(R\) ' and velocity ' \(v\) '
3 Directly proportional to ' \(R\) ' but inversely proportional to ' \(v\) '
4 Inversely proportional to ' \(R\) ' but Directly proportional to velocity ' \(v\) '
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361406 When a ball is released from rest in a very long column of viscous liquid, its downward acceleration is ' \(a\) ' (just after release). Then its acceleration when it has acquired two third of the maximum velocity:

1 \(\dfrac{a}{3}\)
2 \(\dfrac{2 a}{3}\)
3 \(\dfrac{a}{6}\)
4 None of these
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361407 Eight drops of water, each of radius \(2\;mm\) are falling through air at a terminal velocity of \(8\;cm\;{s^{ - 1}}\). If they coalesce to form a single drop, then the terminal velocity of combined drop will be

1 \(30\;cm\;{s^{ - 1}}\)
2 \(28\;cm\;{s^{ - 1}}\)
3 \(24\;\,cm\;{s^{ - 1}}\)
4 \(32\;\,cm\;{s^{ - 1}}\)
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PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361404 A rain drop of radius \(0.3\;mm\) has a terminal velocity in air \(1\;m{s^{ - 1}}.\) The viscosity of air is \(18 \times 10^{-5}\) poise. Find the viscous force on the rain drops.

1 \(2.05 \times {10^{ - 7}}\;N\)
2 \(1.018 \times {10^{ - 7}}\;N\)
3 \(1.05 \times {10^{ - 7}}\;N\)
4 \(2.058 \times {10^{ - 7}}\;N\)
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361405 Spherical balls of radius ' \(R\) ' are falling in a viscous fluid of viscosity ' \(\eta\) ' with a velocity ' \(v\) '. The retarding viscous force acting on the spherical ball is

1 Inversely proportional to both radius ' \(R\) ' and velocity ' \(v\) '
2 Directly proportional to both radius ' \(R\) ' and velocity ' \(v\) '
3 Directly proportional to ' \(R\) ' but inversely proportional to ' \(v\) '
4 Inversely proportional to ' \(R\) ' but Directly proportional to velocity ' \(v\) '
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361406 When a ball is released from rest in a very long column of viscous liquid, its downward acceleration is ' \(a\) ' (just after release). Then its acceleration when it has acquired two third of the maximum velocity:

1 \(\dfrac{a}{3}\)
2 \(\dfrac{2 a}{3}\)
3 \(\dfrac{a}{6}\)
4 None of these
PHXI10:MECHANICAL PROPERTIES OF FLUIDS

361407 Eight drops of water, each of radius \(2\;mm\) are falling through air at a terminal velocity of \(8\;cm\;{s^{ - 1}}\). If they coalesce to form a single drop, then the terminal velocity of combined drop will be

1 \(30\;cm\;{s^{ - 1}}\)
2 \(28\;cm\;{s^{ - 1}}\)
3 \(24\;\,cm\;{s^{ - 1}}\)
4 \(32\;\,cm\;{s^{ - 1}}\)