Fluids Questions and Answers

To make a candle float stably in water in vertical orientation an aluminium cylinder of radius equal to that of the candle is glued at bottom of the candle Length of this cylinder is 1 0 cm and densities of wax aluminium and water are 0 8 g cm 2 7 g cm and 1 0 g cm a Find the maximum and the minimum length 1 of the candle so that it can float in water stably in vertical orientation Radius of the candle is small enough to ignore horizontal shifting of the point of application of the buoyant force b When the candle is lit it consumes wax If consumption of wax reduces length of the candle at a constant rate of 1 0 mm min and initial length of the candle is 12 0 cm how long can the candle be used for lighting always floating vertically

50 A U tube of base length filled with same volume of two liquids of densities p and 2p is moving with an acceleration on horizontal plane If the height difference between the two surfaces open to atmosphere becomes zero then height h is given by nos 3af 2g 09 09 00 60 a 00 2 al 2g

5 A thin walled cylindrical vessel was immersed in an Lideal fluid upto the upper open base At bottom closed end there is an orifice Known height of the vessel h as well as ration of cross sectional area of the orifice to the cross sectional area of the vessel where n 1 Find the time during which the vessel gets filled

2 Three rivers R R2 and R3 merge together to form a river R4 The cross sectional areas of the three rivers R R2 and R3 are in the ratio 1 2 3 and speed of water flowing in these are in the ratio 1 Assuming streamline flow if R4 has cross sectional area equal to that of R the ratio of speed of water in R4 to that in R is A 4 1 B 3 1 C 2 1 D 1 1

Q20 Water rises against gravity in a capillary tube when its one end is dipped into water because a Pressure below the meniscus is less than atmospheric pressure b Pressure below the meniscus is more than atmospheric pressure c Capillary attracts water d Of viscosity

85 Two bodies A and B weigh 10 kg and 20 kg respective MA in water Find the value of M are 2 and 4 respectively MA and MB are mass of A and B respectively 1 if their relative densities 3 2 4 2 1

A solid cube floats in a liquid in a container such that 40 of its volume is floating outside the liquid Now the container is accelerated vertically up by 2g m s The percentage of ball now floating outside the liquid 1 Will be equal to 40 2 Will be less than 40 3 Will not change 4 May increase or decrease depending upon

There is a constant inflow of a liquid into a conical vessel 15 feet deep and 7 5 feet in diameter at the top Water is rising at the rate of 2 feet per minute when the water is 4 feet deep What is the rate if inflow in cu ft per minute

manner through Water flows in a streamlined a capillary tube of radius a the pressure difference being p and the rate of flow Q If the radius is reduced to a 2 and the pressure increased to 2p the rate of flow becomes Question Type Single Correct Type 1 2 4Q Q

arge open tank has two holes in the wall One is a square hole of side L at a depth y from the cop and the other is a circular hole of radius 10 at a depth 4y from the top When the tank is completely filled with water the quantities of water lowing out per second from the holes are both ame Then R is equal to 1 L 2T 2 2nL 3 L 4 18

Q 6 Calculate the velocity with which the liquid gushes out of the 4 cm outlet if the liquid flowing in the tube is water and liquid in U tube has a specific gravity 12 Velocity of liquid at point A is 20 2 m s A 4 cm V 20 2 m s f A 2 cm A3 6 cm 1 2 5 m s 3 8 m s 2 cm p 12000 kg m B A 1cm 2 5 5 m s 4 10 m s 8 m s

A thin plate is floating in a highly viscous liquid of viscosity n contained between two infinite stationary parallel plates The thin plate is acted upon by a constant horizontal force F as shown in figure For the terminal velocity achieved by the rod to be maximum the value of y will be 1 5 2 h h 2h y 2 5 3 h F

If a vessel containing liquid moves down ward with a constant acceleration equal to g then bas a the pressure throughout the liquid mass is atmosphericidad b there will be vacuum in the liquid c d the pressure in the liquid mass is greater than hydrostatic pressure none of the above

Metacentric height for small values of angle of heel is the distance between the a centre of gravity and centre of buoy ancy b centre of gravity and metacentre c centre of buoyancy and metacentre free surface and centre of buoyancy d

The volume of an air bubble is doubled when it rises from the bottom to the surface of a lake The depth of the lake is approximately assume same temperature along depth O 10 2 m O 15 3 m O 20 m 22 m

Centre of buoyancy always b a coincides with the centre of gravity coincides with the centroid of the volume of fluid displaced c remains above the centre of gravity d remains below the centre of gravity

If a graph is drawn between height of liquid inside capillary and rad capillary tube for a given liquid which of the following will it be O Straight line through origin having positive slope O Straight line through origin having negative slope O Rectangular hyperbola O Parabola

The shown figure there is a conical shaft rotating on a bearing of very small clearance t The space between the conical shaft and the bearing is filled with a viscous fluid having coefficient of viscosity n The shaft is having radius R and height h If the external torque applied by the motor is T and the power delivered by the motor is P working in 100 efficiency to rotate the shaft with constant o Ther Answer A B Motor C Your Attempt P T T Tw nR R h 2t TWnR R h 2t C P 2t Tw nR h Correct answer wn R h Rate this questic

View In English Liquid rises in a capillary upto a height of 8 cm The internal and external diameters of a second capillary are double that of first capillary the height of liquid in will be 1 3 Correct Answer 2 8 cm 4 cm 2 cm 1 cm

The position of centre of pressure on a plane surface immersed vertically in a static mass of fluid is b c a at the centroid of the submerged area always above the centroid of the area always below the centroid of the area d none of the above

The total pressure on a plane surface inclined at an angle 0 with the horizontal is equal to a b c pA cos 0 d pA tan 0 where p is pressure intensity at centroid of area and A is area of plane surface pA pA sin 0 3

An oil with a thickness of r cm and a viscosity of 3 2 poises moves over a fixed surface Calculate the velocity gradient and the shear stress at the wall and at a point 3 6 9 cm above it if you know that A The velocity distribution follows the following equation V 12 8y 63y 60y b linear velocity distribution

1 Water rises to a height of 15 mm in a capillary tube having cross sectiona area A If cross sectional area of the tube is made then the water will ris to a height of A 5 2 10 m B 20 3 x 10 m C 10 3 x 10 3 m D 15 3 x 10 3 m

If a liquid has greater cohesion than adhesion with the solid then the liquid in the capillary tube will b a rise with concave surface upward rise with convex surface upward c depress with concave surface upward d depress with convex surface upward

3 Joule Ampere 4 Joule Ampere Select the correct statement regarding stream line 5 flow 1 The momenta of all particles arriving at a point are same 2 The momenta of all particles are same through out the tube 3 The kinetic energy of all particles passing through a point are same 4 Both 1 3 Choose the correct statement 6 3 GG ur and tot van 4 2 1 and a can tur start 3 far un ata t 4 1 3 25 744 2 B B B n BH for A

Calculate the value of the characteristic times for the tiny oildrop in the Millikan oildrop experiment when its terminal speed is 6 1 10 m s A 1x10 s B 9 106 s C 6 2x10 6 S D 2x10 6 S

A spherical metal ball of radius r is lying at the bottom of stationary container containing liquid of density p as shown in the figure The force exerted on the upper hemispherical portion of the sphere due to pressure po atmospheric pressure is A 3 3Po 7rpg 2 C 3Po 7rpg 4r r Tur 2 D 2 r2 3Po 7rpg B 3Po 7rpg

29 In the widest part of the horizontal pipe oil is flowing at a rate of 2 m sec The speed in m s of the flow of oil in the narrow part of the tube if the pressure difference in the broad and narrow parts of the pipe is 0 25 ng is m s

3 There is a air cavity of radius R inside a liquid drop of radius 3R as shown in figure A bubble of radius and made of same liquid is inside air cavity Then the ratio of gauge pressure at point y inside bubble to gauge pressure at point x inside drop is Air Air

Explain your answer westion FIVE Archimedes Principle 2 4 4 State Archimedes principle A cube whose sides measure 1 cm each is submerged in a liquid It experiences a downward pressure of 20 Pa on its ceiling and an upward pressure of 150 Pa on its floor a Calculate the upthrust in N experienced by the cube b Calculate the density of the liquid 20 Pa cube 1 cm each si 150 Pa

5 Water from a tap emerges vertically downward with intial 25 speed 1m s The cross sectional area of tap is 10 m Assume pressure is constant throughout the stream find the velocity of stream 0 15m below the tap 1 V 1 m s 2 V 4 m s 3 V 2m s 4 None of these m s 10 ara fata 0 15m 1 V 1 m s 2 V 4 m s 3 V 2m s 4

Choose the correct answer 1 The bulk modulus of rubber is 9 8 x 108 N m To what depth should a rubber ball be taken in a lake so its volume is decreased by 0 1 Pw 1000 kg m g 9 8 m s 1 25 m 2 100 m 3 200 m 2 A metalic rod of length L and cross sectional area A is made of material of young s modatus Y If the rod is elongated by an amount then the work done in elongation is proportional to 1 e X3 12 4 p2 By inserting a capillary tube upto depth in water the water rises to a height h If the lower end of the capillary tube is closed inside water and capillary is taken out and closed end opened The length of water remain in the tube is Here h 2 1 e 1 1 Zero 3 2 h 4 h A body floats in water with 40 of its volume outside water When same body floats in an oil 60 of its volume remains outside the oil The relative density of oil is 1 0 9 2 1 0 3 1 2 4 1 5 5 A solid sphere falls with a teminal velocity of 10 cm sec in the earth s gravitational field If it is released from rest in a gravity free space then terminal velocity will be heverr tamin 1 Equal to 10 cm sec 2 More than 10 cm sec 3 Equal to 20 cm sec 4 Zero 4 2 h

A water clock used in ancient Greece is designed as vessel with small orifice O The time is determined according to the level of the water in vessel For time scale to be linear the surface of the vessel should be surface of revolution of curve y ax where a is a constant Find the value of n

Figure shows top view of an airplane blown off course by wind in various directions Assume the magnitude of velocity of airplane relative to wind and magnitude of velocity of end to be airplane relative to wind velocity of wind in ground frame 90 W Z 120 E Vas Airplane travels fastest across ground in case d Airplane travels slowest across ground in case c Airplane experiences maximum lateral displacement in case a in none of the cases velocity of wind with respect to air planes can be directed along south west 60 d 30

ally the le tube is uniform and the liquid is incompressible and liquid in the two limbs will be at the same height If the liquid is pressed by y in one limb it will rise by y the length of the tube in the other limb so the restoring force will developed by hydrostatic pressure diffe i e F AP xA h h gdA F Agd sin sini jy h Th As the restoring force is linear motion will be linear simple harmonic m Force constant k Agd sin0 sine So T 2 Adg sin 0 sin 0 Note If the tube is a U tube and liquid is filled to a height h ty

a non linder is rotated about its axis with a constant angular velocity o Uplo a height has shown in the figure Now Find the maximum value of a for which the water will not spill over 20 A 3 R h g H h R ight Advanced 2021 22 Day 4 In CLass Assignment Physics H 14 B w 2 R g H h

A solid block is floating in a liquid as shown in the figure Distance h and are shown in the figure The coefficient of linear expansion of the liquid is Thermal expansion of the solid is negligible 1 List l If the container is moved upward with uniform acceleration II If the block is replaced by another block of similar dimensions but lesser density III If the liquid is replaced by another liquid of equal volume but higher density IV If the temperature of the liquid is increase List Il P Distance decrease Q Buoyant force on the block remains constant R Distance h decreases S Buoyant force on the block increases

Q6 A cylindrical tank contains water up to a height H If the tank is accelerated upwards with acceleration a the pressure at the point A is p If the tank is accelerated downwards with acceleration the pressure at A is p Then a P P2 b P P2 c P P2 d Data insufficient H

Q9 Two syringes of different cross sections without needles filled with water are connected with a tightly fitted rubber tube filled with water Diameters of the smaller piston and larger piston are 1 0 cm and 3 0 cm respectively a Find the force exerted on the larger piston when a force of 10 N is applied to the smaller piston b If the smaller piston is pushed in through 6 0 cm how much does the larger piston move out

A wooden block with metal block which is denser than wood stuck on top of it is floating in water The level of water on the wooden block is marked by line x and level of water in container is marked by line y Now the block is inverted so that metal block is inside water and wooden block is above it Select the CORRECT statement X y A The level of water on wooden block is above x and level of water in container is same as y B The level of water on wooden block is above x and level of water in container is above y C The level of water on wooden block is above x and level of water in container is below y D The level of water on wooden block is below x and level of water in container is above y

s and 0 3 m s 1 A bullet of mass 10 g moving horizontally with a velocity of 400 ms strikes a wooden block of mass 2 kg which is suspended by a light inextensible string of length 5 m As a result the center of gravity of the block is found to rise a vertical distance of 10 cm The speed of the bullet after it emerges out horizontally from the block will be 2016 II a 120 ms c 100 ms 1 b 160 ms d 80 ms

33 A container filled with a liquid of density 4p as shown in the figure The velocity of efflux through orifice is p is density of water and g 10 ms 2 2 1 20 m s 3 14 m s 40 h 5m 2 10 m s 4 28 m s 2 P P

A man of height 1 8 m is in a standing position What is the difference in the blood pressure between the blood in his feet and the topmost level of his head if the density of blood is 1 06 kg m Assume that the blood vessels in a human body act as extremely thin pipes and g 10 m s

A water pump of 1 horse power is required to flow water through a cylindrical pipe line at 1 m s If flow rate of water is to be doubled then the power of new water pump required is 1 1 HP 2 2 HP 3 4 HP 4 8 HP

1 In a simple hydraulic press the cross sectional area of the two cylinders are 5 x 10 m and 102 m respectively A force of 20N is applied at the small plunger What is thrust exerted on the large plunger

The pressure at section 2 shown in Fig Q4 is not to fall below 41 kPa when the flowrate from the tank varies from 0 to 3 m s and the branch line is shut off Determine the minimum height h of the wate tank under the assumption that a minor losses are negligible b mino losses are not negligible 1 8 m T 3m h 182 m with 15 90 elbows All pipe is 15 cm diameter plastic D 0 flanged fittings Branch line 274 m 2 Main line

1 The figure below shows a cylindrical tank filled with water upto a height h A hole is punctured on the side of the tank at a distance r below the water level Water exits the hole and hits a point P at a distance r from the base of the tank Which of the following is true A r is maximum when r h 2 h B r is maximum when r 2 C r is maximum when r h 2h D r is maximum when r h I P

Water is flowing through a pipe as shown in figure Let P P2 and P3 the pressures and V V and v3 be velocities of water at the different sections as 1 V3 shown in figure then P2 P LOY 1 P P P3 2 V V V3 V3

View In English A U tube has 2 tubes of radius 1 mm and 1 5 mm What will be the difference in water level in mm in two limbs Assume Contact angle 8 0 surface tension 7 5 x 10 2 N m 10 m s Correct Answer 5 00 Status unattempted

bas m eesm do 81 A solid cube floats in water half immersed and has Diopil 6 I alsoli small vertical oscillations of time period Hii itslliozo 290g19bau in kg is take g 10 ms 2 a 4 b 2 T 9 c 1 nod TU 5 Its mass d 0 5 the