ECAT Physics Fluid Dynamics Chapter Online Test

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Physics

1. Stoke’s law is applicable to

Motion through horizontal surface

Motion through non-resistive medium

Motion through free space

Motion through viscous medium

2. A particle of mass ‘m’ at rest is acted upon by a force ‘P’ for a time ‘t’. Its kinetic energy after an interval ‘t’ is

Pt/2m

P²t²/m

P²t²/3m

P²t²/2m

3. The decrease in potential energy of a ball of mass 20 kg which falls from a height 50 cm is:

None of these

98 J

968 J

1980 J

4. Three vectors satisfy the relation A . B and A . C = 0, then A is parallel to

C

B . C

B

B x C

5. Stokes law is applicable if body has ___________ shape.

Square

Circular

Rough

Spherical

6. When the fluid is in-compressible, for which the density is

Change

None of these

Both

Constant

7. Equation of continuity is obtained by apply in law of conservation of

Mass

All

Momentum

Energy

8. The terminal velocity of a small size spherical body of radius R moving in a fluid varies as

R²

1/R

R

(1/R)²

9. Which of the following is not the unit of energy?

Electron-volt

Calorie

Joule

Watt

10. Which of the following quantity is dimensionless?

Gravitational constant

None of these

Plank’s constant

Power of lens and gas constant

11. Moment of inertia of an object does not depend upon

Axis of rotation

Angular velocity

Mass of object

Mass distribution

12. If we move from equator to pole, value of g

Remains same

First A and Then B

Decreases

Increases

13. The blood pressure of the person

None

Remains the same

Decreases with age

Increases with age

14. The terminal velocity of for a water droplet of radius 10¯⁵ m is of the order of

1 μm/s

1 nm/s

1 mm/s

1 cm/s

15. Which of these statements is not correct?

Moment of inertia does not depend on mass of body

Moment of inertia is independent of shape and size of the body

None of these

Moment of inertia depends on choice of axes

16. If momentum is increased by 20% then K.E. increases by

66%

77%

44%

55%

17. If a train traveling at 72 kmph is to be brought to rest in a distance of 200 meters, then its retardation should be

20 ms¯²

10 ms¯²

1 ms¯²

2 ms¯²

18. Which of the following sets of concurrent forces may be in equilibrium?

F₁ – 3 N, F₂ – 5 N, F₃ = 9 N

F₁ – 3 N, F₂ – 5N, F₃ = 15 N

F₁ – 3 N, F₂ – 5 N, F₃ = 1 N

F₁ – 3 N, F₂ – 5N, F₃ = 6 N

19. Two boats rowing close to one another tend to collide. This is due to the

Both A and B

None

Pressure between the narrow gap decreases

Air velocity between the narrow gap increases

20. If the water falls from a dam into a turbine wheel 19.6 m below, then the velocity of water at the turbine, is (Take g = 9.8 m/s²)

19.6 m/s

98.0 m/s

9.8 m/s

39.2 m/s

21. An aircraft is moving with a velocity of 300 ms¯¹. If all the forces acting on it are balanced, then

It still moves with the same velocity

It will lose its velocity gradually

It will be fall down instantaneously

It will be just floating at the same point in space

22. A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of particle. The motion of the particle takes place in a horizontal plane. It follows

Velocity is constant

It moves in a circular path

Linear momentum is constant

None of these

23. Force of friction is present in

Liquid

Solid

Gases

All of these

24. A body is subjected to a force such that its velocity is doubled, then

Its potential energy is also doubled

Its kinetic energy is also doubled

Its momentum is also doubled

Its acceleration is also doubled

25. The unit of Planck’s constant h is same as that of

Angular momentum

Linear momentum

Energy

Work

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26. Surface area is

Neither scalar nor vector

Vector

Scalar

Both scalar and vector

27. Two forces of 12 N and 8 N act upon a body. The resultant force on the body has a maximum value of:

0 N

4 N

20 N

8 N

28. An airplane flies 400 m from north and then flies 300 m south and then flies 1200 m unwards then net displacement is

1200 m

1400 m

1500 m

1300 m

29. If an iron ball and a wooden ball of the same radius was released from a height ‘h’ in vacuum, then time taken by both of them to reach ground will be

Roughly equal

Unequal

Zero

Exactly equal

30. The maximum drag force on a falling sphere is 9.8 N, it weight is

Cannot be calculated

9.8 N

4.9 N

1 N

31. Dot product of two mutual perpendicular vector is:

None of these

1

0

∞

32. A truck and a car are moving with equal velocity. On applying the brake both will stop after certain distance then

Both will cover equal distance

None of these

Car will cover less distance before rest

Truck will cover less distance before rest

33. At high altitude the blood oozes out of the nose and near because

The atmospheric pressure decreases there

The blood pressure increase at high altitudes

The percentage of oxygen in the air increase

The density of blood decreases at high altitudes

34. A body whose momentum is constant, must have constant:

Force

None of these

Velocity

Acceleration

35. Two forces P and Q have a resultant perpendicular to P. The angle between the forces is:

tan¯¹(P/Q)

cos¯¹(-P/Q)

tan¯¹(-P/Q)

sin¯¹(P/Q)

36. Unite of impulse in

Joule

Newton

Kg m/s

Kg m

37. A person walks first 10 km north and 20 km east, then the resultant vector is

25.23 km

20 36 km

22.36 km

22.46 km

38. Viscosity of water at 30° C in Nms¯²

0.594 x 10¯³

0.564 x 10¯³

0.521 x 10¯³

0.599 x 10¯³

39. Two insoluble objects seem to lose the same weight when completely submerged in a liquid. The objects must have the same

Weight in the liquid

Weight in water

Weight in air

Density

40. If the force applied is F and the velocity gained is v, then the power developed is

Fv

F/v

Fv²

v/F

41. The ratio of the numerical values of the average velocity and average speed of a body is always.

Less than unity

Unity or less

Unity

Unity or more

42. Two equal forces (P each) act at a point inclined to each other at an angle of 120°. The magnitude of their resultant is

P

2P

P/2

P/4

43. The length breadth and thickness of a block are given by 1 = 12 cm, b = 6 cm and t = 2.45 cm, the volume of the block according to the idea of significant figures should be:

None of these

1 x 10² cm³

1.763 x 10² cm³

2 x 10² cm³

44. The density of water is 10³ kg/m³. The water pressure on a submarine is 2.0 x 10⁷ N/m². The depth of the submarine below the surface of the water, in meters is approximately

200 m

11000 m

8000 m

300 m

45. Which of the following substances has high resistance to flow?

All of these

Mobile oil

Honey

Thick tar

46. The flow is said to be streamline or laminar when every particle

None of these

Moves along the same path as

Moves in different direction

Slowly moves in one direction

47. Height at which value of ‘g’ become one-fourth to hat on earth is:

2R

R

4R

(3/2)R

48. The value of g on the moon whose diameter is ¼ that of earth is 1/6 of that of earth. The ratio of escape velocities at moon and earth’s surface is nearly:

2 : 5

1 : 1

1 : 5

5 : 1

49. If v is the velocity of flow of liquid through a tube of area of cross-section A, then according to equation of continuity

None of these

v/A = constant

Av = constant

A/v = constant

50. Bernoulli’s equation is applicable for

Both laminar and turbulent flow

Laminar flow

None of these

Turbulent flow

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51. When torque acting upon a system is zero which of the following will be constant?

Force

None of these

Linear impulse

Linear momentum

52. What is true between center of gravity and center of mass?

Center of mass changes but center of gravity is always same

Center of gravity changes as one goes away from the earth but center of mass remains same

None of these

They are always at the same point

53. A force of 50 dynes is acted on a body of mass 5 g which is at rest, for an interval of 3 seconds, then impulse is

2.5 x 10¯³ Ns

0.15 x 10¯³ Ns

0.98 x 10¯³ Ns

1.5 x 10¯³ Ns

54. When fluid is incompressible then

Volume of the fluid is constant

Density of the fluid is constant

Flow of the fluid is straight line

Velocity of the fluid is constant

55. If water rises 4 cm in a long, thin tube because of capillary action, then, under corresponding conditions of use, the rise (in the tube) of a liquid whose density is 2 glcm³ will be

2 cm

1 cm

None

8 cm

56. The term Brownian movement refers to

Convection currents in a gas but not in a liquid

The stretching of a body beyond its elastic limit

Irregular motions of small particles suspended in a fluid

Convection currents in a liquid or gas

57. Two bodies with kinetic energies in the ratio of 4 : 1 are moving with equal linear momentum. The ration of their masses is

4 : 1

1 : 1

1 : 4

1 : 2

58. Fire fighters have a jet attached to the head of their water pipes in order to

Avoid wastage of water

Increase the velocity of water flowing out

Increase the volume of water flowing per second

Increase the mass of water flowing per second

59. The motion of planets in the solar system is an example of the conservation of:

Mass

Energy

Angular momentum

Linear momentum

60. If L and R represent inductance and resistance respectively, then dimensional formula of L/R will be

MLT⁰

ML⁰T⁰

M⁰LT²

M⁰L⁰T²

61. At high altitude the blood oozes out of the nose and ear because

The blood pressure increase at high altitudes

The percentage of oxygen in the air increase

The density of blood decreases at high altitudes

The atmospheric pressure decreases there

62. The pressure will be low where the speed of the fluid is

Constant

Low

High

Zero

63. The kinetic energy of a body becomes four ties its initial value. The new linear momentum will be

Thrice the initial value

Same as the initial value

Four times the initial value

Twice the initial value

64. The fluid which is incompressible and non-viscous is called:

Non-ideal fluid

Prefect fluid

All

Ideal fluid

65. Substance which flows easily are

Water

Petrol

Kerosene oil

All of these

66. The low blood pressure is known as

None of these

Systolic

Diastolic

Low blood pressure

67. For a body moving with constant speed in a horizontal circle, which of the following remains constant?

Centripetal force

Acceleration

Velocity

Kinetic energy

68. The atmosphere is held to the earth by

Winds

The rotation of earth

Clouds

Gravity

69. Numerical value of magnitude of a physical quantity is

Inversely proportional to magnitude of the unit

Independent of system of units

Directly proportional to magnitude of the unit

Either (B) or (C)

70. In equation of continuity, if the fluid is incompressible and the flow is steady, the mass of the fluid is

Conserved

Somewhat conserved

None of these

Not conserved

71. The column of mercury is a mercury barometer is 76 cm high on a certain day when the barometer is vertical. If the barometer is tilted a few degrees, the vertical height of the mercury column, h, is

Still 76 cm

76 cm plus the angle

76 cm minus the angle

76 cm minus a function of the angle

72. The high blood pressure is

130 torr

120 torr

110 torr

100 torr

73. For the same kinetic energy, the momentum is maximum for:

An electron

A deuteron

A proton

An α particle

74. Range of a projectile if R, when the angle of projection is 30°. Then, the value of the other angle of projection for the same range, is:

45°

50°

60°

40°

75. At systolic pressure, at the point the first surges of blood flow through the narrow stricture produces

High flow speed

Sound heard

All of these

Initially turbulent

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76. A ball is dropped downwards After 1 second another ball is dropped downwards from the same point. What is the distance between them after 3 seconds?

20 m

50 m

9.8 m

25 m

77. When a bicycle is in motion, the frictional forces exerted by the ground are:

In the backward direction on both the wheels

In the forward direction on the rear wheel

In the forward direction on both the wheels

In the backward direction on the front wheel and the forward direction on the rear wheel

78. The K.E. of a light and a heavy object is same. Which object has maximum momentum?

Both have the same momentum

Data is not sufficient

Heavy object

Light object

79. The torque acting on a body is the rotational analogue of

Force in linear motion

Linear velocity of the body

Linear kinetic energy of the body

Mass of the body

80. A man sitting in a bus traveling in a direction from west to east with a speed of 40 km/h observes that the rain-drops are falling vertically down. To the another man standing on ground the rain will appear

To fall vertically down

The information given is insufficient to decide the direction of rain.

To fall at an angle going from east to west

To fall at an angle going from west to east

81. Distance traveled by a body falling from rest in the first, second and third second is in the ratio of

1 : 3 : 5

None of these

1 : 4 : 9

1 : 2 : 3

82. Two projectiles are fired from the same point with the same speed at angles of projection 60° and 30° respectively. Which one of the following is true?

Their range will be same

Their time of flight will be same

Their landing velocity will be same

Their maximum height will be same

83. Two force are such that then sum of their magnitudes is 18 N and their resultant is perpendicular to the smaller forces and the magnitude of resultant is 12. Then the magnitude of the forces are.

10 N, 8 N

13 N, 5 N

16 N, 2 N

12 N, 6 N

84. In a container having water filled up to a height h, a hole is made in the bottom. The velocity of water flowing out of the hole is

Proportional to h¹⁄ ²

Proportional to h

Independent of h

Proportional to h²

85. If force and displacement of particle in the direction of force are doubled. Work would be

Half

¼ times

Double

4 times

86. A ball is dropped vertically down and it takes time t to reach the ground. At time t/2:

The ball had covered less than half the distance

The velocity of the ball was V/3 where V is the velocity when it reached the ground

The ball had covered exactly half the distance

The ball had covered more than half the distance

87. If unit of length, mass and time each be double, the unit of work done is increased by

4 times

2 times

6 times

8 times

88. Surface tension of water is reduced by adding

Both A and B

Detergents

Camphor

Plastic

89. In a surface tension experiment with a capillary tube water rises up to 0.1 m. If the same experiment is repeated on an artificial satellite, which is revolving around the earth, water will rise in the capillary tube up to a height of

0.1 m

0.2 m

0.98 m

Full length of the capillary tube

90. If solid sphere and solid cylinder of same mass and density rotate about their own axis, the moment of inertia will be greater for

Solid sphere

Both

Equal both

Solid cylinder

91. A projectile on its path gets divided into two pieces at its highest point. Which is true?

Kinetic energy decreases

Momentum increases

Momentum decreases

Kinetic energy increases

92. In case of uniform circular motion which of the following physical quantity do not remain constant?

Momentum

Mass

Speed

Kinetic energy

93. If an object weighs 90 N in air, 60 N in water, and 20 N in an unknown liquid in which it does not dissolve, the so. Gr. Of the unknown liquid is

1.3

1.5

3.0

2.3

94. A thief stole a box with valuable article of weight W and jumped down a wall of height h. Before he reached ground he experienced a load of

2W

W/2

W

Zero

95. Fire fighters have a jet attached to the head of their water pipes in order to:

Increase the volume to water flowing out

Avoid wastage of water

Increase the volume to water flowing per second

Increase the mass of water flowing per second

96. Viscosity of acetone at 30° C in Nsm¯²

0.295 x 10¯³

0.301 x 10¯³

0.224 x 10¯³

0.198 x 10¯³

97. The minimum force required to move a body of mass m vertically upward is:

Mg/2

More than 2mg

More than mg

Mg

98. If a particle covers half the circle of radius R with constant speed then

Change in KE is ½ mv²

Momentum change is mvr

Change in KE is zero

Change in KE is mv²

99. An instrument called a sphygmomanometer measure

Blood pressure

Density of water

Milk density

None of these

100. The blood flow is ____________ flow at disystolic pressure.

Mixed

None of these

Laminar

Turbulent

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101. The two thin tubes which show most correctly the behavior of water are

2 and 3

3 and 4

1 and 2

4 and 5

102. A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle, the motion of the particle takes place in a plane. It follows that

Its kinetic energy is constant

Its moves in straight line

Its velocity is constant

Its acceleration is constant

103. As the droplet accelerates the net force acting on it is

Increase

Decreases

Zero

None of these

104. A container has a small hole in the bottom. Air can go through this hole, but water cannot. This can be best explained by the statement that

Water molecules are larger than molecules in the air

Water contains hydrogen atoms, air does not

Water molecules are smaller than molecules in the air

Surface tension of the water prevents it from

105. Deep water almost runs still when surface water flow in rivers. What does it explains

Magnus effect

Bernoulli’s equation

Surface energy

Equation of continuity

106. When the velocity of a liquid flowing steadily in a tube increases, its pressure?

Decreases

Zero

Increases

Remains same

107. Blood has a density

Greater then water

None of these

Lesser then water

Equal to water

108. The blood vessels are inflated even in

Working state between heart beat

None of these

Occasionally

Relaxed states between heart beat

109. According to equation of continuity A1V1 = A2V2 = constant. The constant is equal to

Density of fluid

Flow rate

Volume of fluid

Mass of fluid

110. Two water pipes of diameters 2 cm and 4 cm are connected with main supply line. The velocity of flow of water in the pipe 2 cm diameter is

Twice

½ of 4 cm diameter pipe

4 times

¼ times

111. The rain drop falling from the sky reach the ground with

Variable speed

Constant terminal velocity

Variable acceleration

Constant acceleration (g)

112. In deriving Bernoulli’s equation, it is assumed that the fluid is

Incompressible

In a steady state

Non-viscous

All of these

113. Pressure exerted by a gas on the walls of its container is due to

Collision between the gas molecules and the container

Adhesion between the gas molecules and the container

Cohesion between the gas molecules and the container

Surface tension of the gas

114. Viscosity of glycerin at 30° C in Nsm¯²

6.49 x 10¯³

6.18 x 10¯³

6.29 x 10¯³

6.12 x 10¯³

115. The kinetic energy of a body of mass 2 kg and momentum of 2 Ns is

1 J

2 J

3 J

4 J

116. A car is moving high velocity when it takes a turn. A force acts on it outwardly because of

Gravitational force

All of these

Centripetal force

Centrifugal force

117. The vector sum of two forces is perpendicular to their vector difference. In that case, the forces

Cannot be predicted

Are equal to each other in magnitude

Are equal to each other

Are not equal to each other in magnitude

118. If the spinning speed of the earth is increased, then the weight of the body at equator

Doubles

Decreases

Increases

Does not change

119. The dimensions of the quantities in one of the following pairs are the same. Identify the pairs.

Energy and Young’s modulus

Light year and time

Torque and work

Angular momentum and work

120. For a given angle of projection, if the time of flight of a projectile is doubled, the horizontal range will increases to:

Four times

Once

Thrice

Twice

121. If the acceleration due to gravity at the earth’s surface is 9.8 m/s² and the mass of the earth is 90 times that of the moon and radius of earth 4 times that of moon, the value of G at the moon’s surface will be:

9.8 m/s²

4.9 m/s²

None of these

1.96 m/s²

122. Which of the following is true?

Momentum is conserved in all collisions but kinetic energy is conserved only in inelastic collisions

Both momentum and kinetic energy are conserved in all collisions

Neither momentum nor kinetic energy is conserved in inelastic collisions

Momentum is conserved in all collisions but not kinetic energy

123. The motion of planets in the solar system is an example of conservation of:

Mass

Kinetic energy

Angular momentum

Momentum

124. A body of mass 5 kg is moving with a momentum of 10 kg m/s. A force of 0.2 N acts on it in the direction of motion of the body for 10 seconds. The increase in its kinetic energy is

3.8 joule

2.8 joule

4.4 joule

3.2 joule

125. The range of projectile is 50 m when θ is inclined with horizontal at 15°. What is the range when θ becomes 45°?

400 m

300 m

200 m

100 m

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126. A body falls freely from rest. It covers as much distance in the last second of its motion as covered in the first three seconds. The body has fallen for a time of

5 s

3 s

7 s

9 s

127. The low blood pressure is

79 – 80 torr

75 – 80 torr

78 – 809 torr

70 – 80 torr

128. Two forces of 4 dyne and 3 dyne act upon a body. The resultant force on the body can only be

More than 3 dynes

Between 1 and 7 dyne

More than 4 dynes

Between 3 and 4 dyne

129. The unit of focal power of a lens is

Kilo watt

Horse power

Diopter

Watt

130. Venturi relation is used measure

Density of the liquid

Pressure of the liquid

Height of the pipe

Speed of liquid flow

131. A boat of mass 40 kg is at rest. A dog of mass 4 kg moves in the boat with a velocity of 10 m/s. What is the velocity of boat?

1 m/s

8 m/s

2 m/s

4 m/s

132. In a uniform circular motion (horizontal) of a ball tied with a string, velocity at any time is at any angle θ with acceleration, then θ is

θ = 90°

θ = 60°

θ = 30°

None of these

133. The equation of continuity of fluid is based on the

All of these

Law of conservation of momentum

Law of conservation of mass

Law of conservation of energy

134. A man standing near a fast moving train may fall

Towards the train

On the train

Away from the train

On himself

135. The escape velocity from the earth’s surface is 11 km/s. A certain planet has a radius twice that of the earth but its mean density is the same as that of the earth. The value of the escape velocity from this planet would be:

16.5 km/s

5.5 km/s

22 km/s

11 km/s

136. The number of significant figures in all the given number 25.12, 2009, 4.156 and 1.257 x 10¯⁴ is

1

4

3

2

137. The angular momentum of a system of particles is not conserved

When a net eternal torque is acting upon the system

None of these

When a net external impulse is acting upon the system

When net external force is acting upon the system

138. The relation P₁ – P₂ = ½ PV₂² shows the

Bernoulli’s equation

None of these

Torricelli’s theorem

Venturi relation

139. A ball is dropped from a certain height and another ball is projected horizontally from the same point. Which of the following statements is correct?

The change of speed during the path for both balls is the same

The change of velocity during the path for both balls is the same

Both hit the ground at the same velocity

Both hit the ground at the same speed

140. If a person with a spring balance and a body hanging from it goes up and up in an airplane, then the reading of the weight of the body as indicated by the spring balance, will

Remains the same

Go no increasing

First increase and then decrease

Go on decreasing

141. In Torricelli’s theorem, the speed of efflux is equal to

(h₁ – h₂) and falling under gravity

h₁ – h₂

Action of gravity

None of these

142. A car covers 1/3 distance with speed 20 km/hr and 2/3 with 60 km/h. Average speed is

40 km/h

36 km/h

80 km/h

50√2 km/h

143. A train is moving with a velocity of 25 m/s and a car is moving behind it by a velocity of 8 m/s in same direction. The relative velocity of train with respect to car is

33 m/s

17.5 m/s

17 m/s

None of these

144. According to Stoke’s law, drag force depends on

Initial velocity

Final velocity

Terminal velocity

Instantaneous velocity

145. A body is thrown from a height h with speed u, it hits the ground with speed V

The value of V does not depend on the direction of which it is thrown

The value of V is maximum if the body is thrown vertically downward

The value of V is minimum if the body is thrown horizontally

The value of V is maximum if the body is thrown vertically upwards

146. The angular momentum of a body is conserved if

Torque acting on it is constant

Force acting on it is constant

Torque acting on it is zero

Force acting on it is zero

147. Angular momentum has the same unit as

Linear momentum x time

Work x frequency

Power x time

Impulse x distance

148. When a body is moving on a surface, the force of friction is called

Static friction

Limiting friction

Dynamic friction

Rolling friction

149. If a force acts on a body, whose action line does not pass through its center of gravity, then the body will experience

Linear acceleration

None of these

No acceleration

Angular acceleration

150. In an elevator moving vertically up with an acceleration ‘g’, the force exerted on the floor by a passenger of mass M is

Mg

Zero

2 Mg

½ Mg

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151. Which of the following is not a perfectly inelastic collision?

A man jumping onto a moving cart

An electron captured by a proton

Striking of two glass balls

A bullet striking a bag of sand

152. In case of streamed lined flow of liquid, the loss of energy is

Infinite

Maximum

Minimum

Zero

153. Wb/m² is equal to

Tesla

Henry

Watt

Dynes

154. At high speeds the force is no longer

Proportional

No proportion

None of these

Simply proportional

155. At terminal velocity, fluid friction is

Maximum

Minimum

Zero

None of these

156. If the K.E. of a body becomes four times of the initial value, then new momentum will

Become four times, its initial value

Become twice its initial value

Become three times, its initial value

Remains constant

157. The rain drop falling from the sky reach the ground with

Variable acceleration

Constant acceleration (g)

Variable speed

Constant terminal velocity

158. You are on a frictionless horizontal plane. How can you get off if no horizontal force is exerted by pushing against the surface?

By running on the plane

By jumping

By spitting or sneezing

By rolling your body on the surface

159. The smooth or steady stream-line flow is know as

Laminar flow

None of these

Turbulent flow

Both a and b

160. The direction of the angular velocity vector is along

The inward radius

The outward radius

The axis of rotation

The tangent to the circular path

161. Which of the following quantities is a vector

Volume

Density

Displacement

Temperature

162. The resultant of two equal force is double of either of the force. The angle between them is

60°

120°

0°

90°

163. Drag force is given by

Newton’s law

Pascal’s law

Stokes law

Gauss law

164. The Bernoulli’s equation is based on the

Law of conservation of energy

All of these

Law of conservation of momentum

Law of conservation of mass

165. Rocket engines lift a rocket from the earth surface, because hot gas with high velocity

React against the rocket and push it up

Push against the air

Heat up the air which lifts the rocket

Push against the earth

166. If vectors P, Q and R have magnitude 5, 12 and 13 units and P + Q = R, the angle between Q and R is

cos¯¹12/13

cos¯¹ 5/13

cos¯¹ 7/13

cos¯¹ 5/12

167. The physical quantity which has the dimensional formula M¹T¯³ is

Solar constant

Surface tension

Density

Compressibility

168. The acceleration of a motor car is 8 m/s². If the diameter of its wheel be 2 meter, its angular acceleration will be

8 radian/s²

8 m/s²

16 radian/s²

16 m/s²

169. Viscosity of ethanol at 30° C in Nsm¯²

1.000 x 10¯³

1.012 x 10¯³

0.954 x 10¯³

1.014 x 10¯³

170. The ability of a fluid to resist force is called

Elasticity

Ductility

Strength

Stiffness

171. Burnoullis equation is obtained by applying law of conservation of _________.

Fluid

Mass

Energy

Momentum

172. When two surfaces are coated with a lubricant, then they

Roll upon each other

Stick to each other

Slide upon each other

None of these

173. Water is filled up to a height ‘H’ in a tank. A hole is made at depth ‘h’ below the water level. The velocity of efflux of the fluid is

2gh

√gh

gh

√2gh

174. Bernoulli’s equation is based upon law of conservation of

None

Momentum

Mass

Energy

175. Terminal velocity of the body is directly proportional to the

Radius of the body

Size of the body

Diameter of the body

Square of the diameter of the body

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176. A ball of mass m₁ and another ball of mass m₂ are dropped from equal heights. If time taken by the balls are t₁ and t₂ respectively then

t₁ = 4t₂

t₁ = t₂/4

t₁ = t₂/2

t₁ = t₂

177. A flowing liquid possesses

All

P.E.

K.E.

Pressure Energy

178. Coefficient of viscosity of honey is greater than

Alcohol

Milk

Petrol

Water

179. With increase of temperature, the viscosity of liquid and gases

Increases for both

Increase for liquids and decreases for gases

Decrease for liquids and increase for gases

Decrease for both

180. If rope of lift breaks suddenly. The tension exerted by the surface of life is (a = Acceleration of lift)

0

M(g + a)

M(g – a)

Mg

181. Which of the following statements for an object in equilibrium is not true?

The object must be at rest

The object can be at rest

The object is moving at constant speed

The acceleration of the object is zero

182. A stone is dropped from rest from the top of a tower 19.6 m high. The distance traveled during the last second of its fall is (giving g = 9.8 m/s²)

4.9 m

19.6 m

14.7 m

9.8 m

183. If the earth suddenly stops rotating the value of ‘g’ at equator would:

Become zero

Increase

Decrease

Remain unchanged

184. A tube is tapered from 20 cm diameter to 2 cm diameter, the velocity at the first cross-section is 50 cm/s, then the velocity at the second cross-section is

50 m/s

5 m/s

5 cm/s

50 cm/s

185. The Systolic blood pressure comes when

Vessel collapse

All of these

None of these

Cutting off the blood flow

186. A chimney works best if air exposed to the chimmey is

Stationary

Moving

Moving slowly

Moving fast

187. A car travels first half distance between two places with a speed of 30 km/h and remaining half with a speed of 50 km/h. The average speed of the car is

37.5 km/h

42 km/h

40 km/h

10 km/h

188. Velocity of fluid increases where the pressure is

High

Constant

Changes continuously

Low

189. The mass of the block is

21,000 g

3000 g

None of these

30001 b

190. Even the small viscosity of the air causes a retarding force on car at high speed is

Large

Very large

Small

None of these

191. S.I unit of magnetic flux is

Weber

Weber per metre

Weber metre¯²

Weber per metre⁴

192. A pendulum of time period T is kept suspended in a train accelerating uniformly, then its time period

Decreases

None of these

Increases

Remains unchanged

193. Two bullets are fired simultaneously, horizontally and with different speeds from the same place. Which bullet will hit the ground first?

The slower one

The faster one

Both will reach simultaneously

Depends on their mass

194. Which one of the following groups have quantities that do not have the same dimensions?

Force, impulse

Pressure, stress

Work, energy

Velocity, speed

195. The rectangular components of force 5 dyne are

3 and 4 dyne

2 and 3 dyne

2.5 and 25 dyne

1 and 2 dyne

196. Two bodies of masses 1 kg and 5 kg are dropped gently from the top of a tower. At a point 20 cm from the ground both the bodies will have the same

Total energy

Velocity

Momentum

Kinetic energy

197. Angular momentum is

A vector

Neither A. nor B.

Either A. or B.

A scalar

198. Pick out the wrong pair:

Charge-coulomb

Temperature-thermometer

Sp. gravity-hygrometer

Pressure-barometer

199. Swimming is based on the principle of

Newton’s 2nd law

All

Newton’s 1st law

Newton’s 3rd law

200. Which of the following is the smallest unit?

Meter

Fermi

Millimeter

Angstrom

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201. A jet engine works on the principle of

Conservation of angular momentum

Conservation of linear momentum

Conservation of energy

Conservation of mass

202. The force exerted by the fluid in a hydraulic press on the piston is 2000 N. If the area of the piston is 10 cm², the fluid pressure on the piston is, in N/cm²

20

200

20,000

2000

203. Ball pen functions on the principle of

Viscosity

Surface tension

Gravitational force

Boyle’s law

204. A railway engine (mass 10⁴ kg) is moving with a speed of 73 km/h. The force which should be applied to bring it to rest over a distance of 20 m is

3,600 N

10,000 N

7,200 N

100,000 N

205. With the increase of temperature viscosity

Remains same

Doubles

Decrease

Increase

206. V = √2g(h₁ – h₂) shows the

None of these

Torricelli’s theorem

Equation of continuity

Bernoulli’s theorem

207. When a horse pulls a cart, the force that makes the horse run forward is the force exerted by

The horse on the cart

The ground on the cart

The ground on the horse

The horse on the ground

208. A body of mass 1.0 kg is falling with an acceleration of 10 m/s². Its apparent weight will be (g = 10 m/s²)

0.5 kg wt

2.0 kg wt

Zero

1.0 kg wt

209. Internal friction of fluid is called

Resistance

Viscosity

Surface tension

Cohesive force

210. Length cannot be measured by

Light year

Fermi

Debye

Micron

211. The velocity of falling raindrops attains limited value because of

Viscous force exerted by air

Air currents of the earth atmosphere

Up thrust of air

Surface tension effect

212. A particle is moving in a vertical circle. The tensions the string when passing through two positions at angles 30° and 60° from vertical (lowest positions) are T₁ and T₂ respectively. Then

T₁ = T₂

Tension in the string always remains the same

T₂ > T₁

T₁ > T₂

213. The mass of fluid passing through any cross-section per unit time is called

Both a and b

Magnetic flux

Electric flux

Mass flux

214. A cold soft drink is kept on the balance. When the cap is opened, then the weight

Decreases

Remains same

First increases, then decreases

Increases

215. Find the total displacement of a body in 8 seconds starting from rest with an acceleration of 20 cm/s²

64 cm

0.064 m

640 cm

64 m

216. The maximum and minimum magnitudes of the resultant of two given vectors are 17 units and 7 units respectively. If these two vectors are at right angles to each other, the magnitude of their resultant is

16

13

18

14

217. The maximum velocity of an object falling freely through air is called

Instantaneous velocity

Final velocity

Initial velocity

Terminal velocity

218. If A x B = B x A, then the angle between A and B is

π

π/3

π/4

π/2

219. When a body moves in a circular path, no work is done by the force since.

Force and displacement are perpendicular to each other

The force is always away from the center

There is no displacement

There is no net force

220. A particle undergoes uniform circular motion. About which point on the plane of the circle, will the angular momentum of the particle remain conserved?

Outside the circle

Center of the circle

Inside the circle

On the circumference of the circle

221. Two bodies of mass 1 kg and 2 kg have equal momentum. Then, the ratio of their kinetic energies is

3 : 1

1 : 1

2 : 1

1 : 3

222. If speed of electron is 5 x 10⁵ m/s. How long does it take one electron to traverse 1 m?

1 x 10⁵ s

1 x 10⁶ s

2 x 10⁵ s

2 x 10⁶ s

223. The electrical forces between the molecules of a liquid are

Attractive

Repulsive

Both A and B

None

224. A force of 10 N displace an object by 10 m. If work done is 50 J then direction of force makes an angle with direction of displacement.

None of these

120°

90°

60°

225. The maximum drag force on a falling sphere is 9.8 N, it weight is

1 N

9.8 N

Cannot be calculated

4.9 N

Page 10 of 11

226. The resultant of two forces, one double the other in magnitude, is perpendicular to the smaller of the two forces. The angle between the two forces is

60°

120°

90°

150°

227. The percentage errors in the measurement of mass and speed are 3% and 4% respectively. The maximum error in the measurement of kinetic energy is:

9%

8%

10%

11%

228. A motorcycle driver double its velocity when he is having a turn. The force exerted outwardly will by

Half

4 times

¼ time

Double

229. The unit of inductance is equivalent to

Volt/ampere x second

Volt x ampere/second

Ampere/volt x second

Volt x second/ampere

230. Identify the pair whose dimensions are equal

Stress and energy

Force and work

Force and stress

Torque and work

231. Water is filled up to a height ‘H’ in a tank. A hole is made at depth ‘H’ below the water level. The velocity of efflux of the fluid is.

2gh

√gh

√2gh

.gh

232. A man fires a bullet of mass 200 g at a speed of 5 m/s. The gun is of one kg mass. By what velocity the gun rebounds backwards?

0.01 m/s

0.1 m/s

10 m/s

1 m/s

233. The pressure will be low where the speed of the fluid is

High

Zero

Low

Constant

234. The apparent loss in weight of the block in the liquid is

21 N

60 N

15 N

30 N

235. A pendulum bob is suspended inside a lift moving upward with constant velocity. If mass of the bob is 50 g then its weight inside the compartment is

0.05 N

N

Zero

0.5 N

236. The dimensions of Planck’s constant is equal to that of

Power

Momentum

Angular momentum

Energy

237. A 50 kg man with 20 kg load on his head climbs up 20 steps of 0.25 m height each. The work done in climbing is

5 J

350 J

100 J

3430 J

238. In case of streamed lined flow of liquid, the loss of energy is

Infinite

Equal to what is in turbulent flow

Maximum

Minimum

239. Two forces of magnitude 7 N and 5 N act on a particle at an angle θ to each other, θ can have any value. The minimum magnitude of the resultant force is

8 N

2 N

12 N

5 N

240. What is the weight of a 700 g of body on a planet whose mass is 1/7th of that of earth and radius is ½ of earth?

500 gf

700 gf

300 gf

400 gf

241. For keeping a body in circular motion, the force required is

Centripetal

Centrifugal

Tangential

Radial

242. If a body starts from rest and travels 120 cm in the 6th second then what is the acceleration?

0.20 m/s²

0.027 m/s²

0.218 m/s²

0.03 m/s²

243. The Drag force increases as the speed of the object

Increases

Decreases

None of these

Decreases rapidly

244. The momentum of particle is numerically equal to its kinetic energy. What will be the velocity of the particle?

2 m/s

None of these

1 m/s

4 m/s

245. The work done in taking a particle from the floor to a table depends on

The speed of the particle

The actual path taken

The time taken in this work

The height of the table

246. When a bicycle is in motion but not pedaled, the force of friction exerted by the ground on the two wheels is such that it acts

In the backward direction on the front wheel and in the forward direction on the rear wheel

In the forward direction on bath the wheels

In the forward direction on the front wheel and in the backward direction on the rear wheel

In the backward direction on both the wheels

247. A body is floating in a liquid. The up thrust on the body is

Zero

Weight of body-weight of liquid displaced

Less than the weight of liquid displaced

Equal to weight of liquid displaced

248. If the acceleration due to gravity is 10 ms¯² and the units of length and time are changed to kilometer and hour respectively, the numerical value of acceleration in

72000

360000

36000

129600

249. A light body A and a heavy body B have equal linear momentum. Then the K.E. of the body A

Is greater than that of B

Is smaller than that of B

Is equal to that of B

Is zero

250. A flowing liquid possesses

P.E.

Pressure Energy

K.E.

All

Page 11 of 11

251. Above a certain velocity the fluid flow, the motion of the fluid becomes:

Unsteady

B and C

Steady

Irregular

252. A person is standing on a rotating stool spreading his arms. He suddenly contracts his arms. His

Angular momentum decreases

Angular momentum increases

Moment of inertia increases

Moment of inertia decreases

253. When body moves with terminal velocity the acceleration in the body become

Variable

Infinite

Zero

Maximum

254. The centripetal force for a car moving on a road is given by

Friction due to tyres

The drive of the car

Force of brakes

Force by steering wheel

255. The electrical forces are

None

Repulsive

Attractive

Both A and B

256. Reason of weightlessness in a satellite is

Center of mass

Zero gravity

Zero reaction force by satellite surface

None of these

257. Angular momentum is

Polar vector

At 45° angle

Axial vector

Scalar

258. A chimney works best when it is

Not tall but wide

Exposed to air currents

A and B

Tall

259. A ball whose kinetic energy is E, is thrown at an angle of 45° with the horizontal, its kinetic energy at the highest point of its flight will be

E/2

F/√2

E

Zero

260. In a uniform circular motion

Velocity and acceleration remain constant

Kinetic energy remain constant

Speed and acceleration change

Only velocity change, acceleration remain constant

261. If v is the velocity of flow of liquid through a tube of area of cross-section A, then according to equation of continuity

A/v = constant

v/A = constant

Av = constant

None

262. A body moving in a circular path with constant speed has

Variable speed and constant velocity

Constant retardation

Constant acceleration

Variable acceleration

263. Maximum height of a bullet when fired at 30° with horizontal is 11 m. Then height when it is fired at 60° is

6 m

33 m

22 m

7.8 m

264. A particle is moving in a circle with uniform speed v. In moving from a point to another diametrically opposite point,

The momentum changes by 2mv

The momentum changes by mv

The kinetic energy changes by (1/2)mv²

The kinetic energy changes by mv²

265. Angular momentum of a body is defined as the product of

Mass and angular velocity

Centripetal force and radius

Moment of inertia and angular velocity

Linear velocity and angular velocity

266. The concentration of red blood cells in blood is

– 45%

– 40%

~ 50%

~ 30%

267. At the top of the trajectory of a projectile, the directions of its velocity and acceleration are

Parallel to each other

Antiparallel to each other

Perpendicular to each other

Inclined to each other at an angle of 45°

268. The energy associated with an electron of velocity 10⁶ m/s is:

4.5 x 10¯¹⁰ J

4.5 x 10¯¹⁹ J

3 x 10¯¹⁹ J

3 x 10¯¹⁰ J

269. When the velocity of a liquid flowing steadily in a tube increases, its pressure?

Decreases

Zero

Remains same

Increases

Total Questions:	269
Time Allowed:	120 Minutes
Total Marks:	269
How to Attempt Test:	Please choose the right Option in MCQ-type question.
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ECAT Physics Fluid Dynamics Online Test

ECAT Physics Fluid Dynamics Online Test