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Here we know that for turbulent flow, we need a certain limit of Reynolds number. So, what is Reynold's number?

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Important Questions on Properties of Matter

EASY

Physics>Mechanics>Properties of Matter>Critical Velocity

The velocity of upper layer of water in a river is

36 km h^{- 1}

. Shearing stress between horizontal layers of water is

10^{- 3} N m^{- 2}

. Depth of the river is _____

m

. (Co-efficient of viscosity of water is

10^{- 2} Pa s

)

EASY

Physics>Mechanics>Properties of Matter>Critical Velocity

A flat plate of area $10 {cm}^{2}$ is separated form a large plate by a layer of Glycerine $1 mm$ thick. If the coefficient of viscosity of Glycerine is $20$ poise, the force required to keep the plate moving with a velocity of $1 cm s^{- 1}$ is

EASY

Physics>Mechanics>Properties of Matter>Critical Velocity

p

is the density and

η

is coefficient of viscosity of fluid which flows with a speed

v

in the pipe of diameter

d

, the correct formula for Reynolds number

R_{e}

HARD

Physics>Mechanics>Properties of Matter>Critical Velocity

The Bhagirathi and the Alaknanda merge at Deoprayag to form the Ganga with their speeds in the ratio

1 : 1 : 5 .

The cross-sectional areas of the Bhagirathi, the Alaknanda and the Ganga are in the ratio

1 : 2 : 3 .

Assuming streamline flow, the ratio of the speed of Ganga to that of the Alaknanda is

MEDIUM

Physics>Mechanics>Properties of Matter>Critical Velocity

A solid sphere of volume

V

experiences a viscous force

F

when descending with a speed

v

in a liquid. If another solid sphere of volume

27 V

descends with the same speed

v

in the same liquid, it experiences a viscous force

EASY

Physics>Mechanics>Properties of Matter>Critical Velocity

The cylindrical tube of a spray pump has radius

R

, one end of which has

n

fine holes, each of radius

r

. If the speed of the liquid in the tube is

V

, the speed of the ejection of the liquid through the holes is :

EASY

Physics>Mechanics>Properties of Matter>Critical Velocity

Oil is used for frying food materials rather than water, since oil

MEDIUM

Physics>Mechanics>Properties of Matter>Critical Velocity

Water flows in a horizontal tube (see figure). The pressure of water changes by

700 N m^{- 2}

between

A

and

B

where the area of cross section are

40 {cm}^{2}

and

20 {cm}^{2},

respectively. Find the rate of flow of water through the tube. (density of water

= 1000 kg m^{- 3}

)

HARD

Physics>Mechanics>Properties of Matter>Critical Velocity

A steel ball is dropped in a viscous liquid. The distance of the steel ball from the top of the liquid is shown below. The terminal velocity of the ball is closest to

Question Image

MEDIUM

Physics>Mechanics>Properties of Matter>Critical Velocity

The velocity of a small ball of mass

M

and density

ρ

, when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is

\frac{ρ}{2}

, then the viscous force acting on the ball will be:

MEDIUM

Physics>Mechanics>Properties of Matter>Critical Velocity

Water containing air bubbles flows without turbulence through a horizontal pipe which has a region of narrow cross-section. In this region the bubbles

EASY

Physics>Mechanics>Properties of Matter>Critical Velocity

The velocity of water in a river is

18 km h^{- 1}

near the surface. If the river is

5 m

deep, find the shearing stress between the horizontal layers of water. The coefficient of viscosity of water

= 10^{- 2} poise

MEDIUM

Physics>Mechanics>Properties of Matter>Critical Velocity

Water is flowing at a speed of 1.5 m s^-1 through a horizontal tube of cross-sectional area 10^-2 m²and you are trying to stop the flow by your palm. Assuming that the water stops immediately after hitting the palm, the minimum force that you must exert should be (density of water = 10³ kg m^-3)

MEDIUM

Physics>Mechanics>Properties of Matter>Critical Velocity

The velocity of water in a river is

18 km h^{- 1}

near the surface. If the river is

5 m

deep, find the shearing stress between the horizontal layers of water. The coefficient of

viscosity of water = 10^{- 2} poise

MEDIUM

Physics>Mechanics>Properties of Matter>Critical Velocity

Water from a tap emerges vertically downwards with an initial speed of

1.0 m s^{- 1}

. The cross

-

sectional area of the tap is

10^{- 4} m^{2}

. Assume that the pressure is constant throughout the stream of water and that the flow is streamlined. The cross

-

sectional area of the stream,

0.15 m

below the tap would be:
(Take

g = 10 m s^{- 2}

)

EASY

Physics>Mechanics>Properties of Matter>Critical Velocity

Water flows through a horizontal pipe of diameter

2 cm

at a speed of

3 cm s^{- 1}

. The pipe has a nozzle of diameter

0.5 cm

at its end. The speed of water emerging from the nozzle is

MEDIUM

Physics>Mechanics>Properties of Matter>Critical Velocity

An ideal fluid flows (laminar flow) through a pipe of non-uniform diameter. The maximum and minimum diameters of the pipes are

6.4 c m

and

4.8 c m

, respectively. The ratio of the minimum and the maximum velocities of fluid in this pipe is:

EASY

Physics>Mechanics>Properties of Matter>Critical Velocity

Identify the incorrect statement regarding Reynold's number

(R_{e}) :

HARD

Physics>Mechanics>Properties of Matter>Critical Velocity

Water from a pipe is coming at a rate of

100

liters per minute. If the radius of the pipe is

5 c m,

the Reynolds number for the flow is of the order of: (density of water =

100 k g / m^{3},

coefficient of viscosity of water

= 1 m P a s)

MEDIUM

Physics>Mechanics>Properties of Matter>Critical Velocity

If it takes 5 minutes to fill a 15 litre bucket from a water tap of diameter

\frac{2}{\sqrt{π}} c m

then the Reynolds number for the flow is (density of water =

10^{3} k g / m^{3} a n d v i s c o s i t y o f w a t e r = 10^{- 3} P a . s

) close to:

Here we know that for turbulent flow, we need a certain limit of Reynolds number. So, what is Reynold's number?

Important Questions on Properties of Matter

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