ECAT Physics Fluid Dynamics Chapter Online Test

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Physics

1. The Bernoulli’s equation is based on the

Law of conservation of momentum

Law of conservation of mass

All of these

Law of conservation of energy

2. 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?

Both hit the ground at the same speed

Both hit the ground at the same velocity

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

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

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

Angular velocity

Mass of object

Mass distribution

Axis of rotation

4. 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

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

Mixed

Laminar

None of these

Turbulent

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

Light object

Both have the same momentum

Heavy object

Data is not sufficient

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

Unity or less

Unity or more

Unity

Less than unity

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

Energy

Angular momentum

Mass

Linear momentum

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

Constant

High

Zero

Low

10. 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

W

Zero

W/2

2W

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

Between 3 and 4 dyne

More than 3 dynes

Between 1 and 7 dyne

More than 4 dynes

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

0.954 x 10¯³

1.012 x 10¯³

1.014 x 10¯³

1.000 x 10¯³

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

2 x 10⁶ s

1 x 10⁶ s

2 x 10⁵ s

1 x 10⁵ s

14. 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

0.5 N

Zero

N

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

Angular acceleration

No acceleration

None of these

Linear acceleration

16. 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

Momentum

Total energy

Kinetic energy

Velocity

17. Stoke’s law is applicable to

Motion through horizontal surface

Motion through non-resistive medium

Motion through viscous medium

Motion through free space

18. 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°

60°

50°

40°

19. The unit of inductance is equivalent to

Volt/ampere x second

Volt x ampere/second

Ampere/volt x second

Volt x second/ampere

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

Conserved

Not conserved

None of these

Somewhat conserved

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

Slowly moves in one direction

None of these

Moves in different direction

Moves along the same path as

22. 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

76 cm minus the angle

76 cm plus the angle

Still 76 cm

76 cm minus a function of the angle

23. 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

Twice the initial value

Four times the initial value

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

1/R

R

(1/R)²

R²

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

Air currents of the earth atmosphere

Viscous force exerted by air

Surface tension effect

Up thrust of air

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

Pressure, stress

Velocity, speed

Work, energy

Force, impulse

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

Power

Angular momentum

Momentum

Energy

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

F₁ – 3 N, F₂ – 5 N, F₃ = 1 N

F₁ – 3 N, F₂ – 5N, F₃ = 6 N

F₁ – 3 N, F₂ – 5N, F₃ = 15 N

F₁ – 3 N, F₂ – 5 N, F₃ = 9 N

29. Venturi relation is used measure

Speed of liquid flow

Height of the pipe

Pressure of the liquid

Density of the liquid

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

When net external force is acting upon the system

When a net eternal torque is acting upon the system

None of these

When a net external impulse is acting upon the system

31. Swimming is based on the principle of

Newton’s 1st law

All

Newton’s 3rd law

Newton’s 2nd law

32. The term Brownian movement refers to

Convection currents in a gas but not in a liquid

Irregular motions of small particles suspended in a fluid

Convection currents in a liquid or gas

The stretching of a body beyond its elastic limit

33. 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

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

Kinetic energy increases

Momentum increases

Kinetic energy decreases

Momentum decreases

35. Internal friction of fluid is called

Resistance

Surface tension

Cohesive force

Viscosity

36. 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

37. 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 at an angle going from east to west

To fall vertically down

To fall at an angle going from west to east

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

38. The low blood pressure is known as

Diastolic

None of these

Low blood pressure

Systolic

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

Acceleration

Kinetic energy

Centripetal force

Velocity

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

None of these

Action of gravity

(h₁ – h₂) and falling under gravity

h₁ – h₂

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

16 radian/s²

8 radian/s²

16 m/s²

8 m/s²

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

1 mm/s

1 cm/s

1 nm/s

1 μm/s

43. The low blood pressure is

75 – 80 torr

79 – 80 torr

78 – 809 torr

70 – 80 torr

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

Increase the volume to water flowing out

Increase the mass of water flowing per second

Increase the volume to water flowing per second

Avoid wastage of water

45. Ball pen functions on the principle of

Surface tension

Boyle’s law

Gravitational force

Viscosity

46. Wb/m² is equal to

Dynes

Henry

Tesla

Watt

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

Surface energy

Bernoulli’s equation

Magnus effect

Equation of continuity

48. 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 more than half the distance

The ball had covered exactly half the distance

49. 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

Twice

Thrice

50. The high blood pressure is

130 torr

100 torr

120 torr

110 torr

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

4 m/s

1 m/s

2 m/s

None of these

52. Which of the following quantity is dimensionless?

None of these

Gravitational constant

Plank’s constant

Power of lens and gas constant

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

1980 J

None of these

98 J

968 J

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

Weight in water

Weight in air

Density

Weight in the liquid

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

The force is always away from the center

There is no displacement

Force and displacement are perpendicular to each other

There is no net force

56. The atmosphere is held to the earth by

Clouds

Gravity

The rotation of earth

Winds

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

Mass

Energy

Momentum

Fluid

58. 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

4.4 joule

3.2 joule

3.8 joule

2.8 joule

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

R

(3/2)R

2R

4R

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

Force

Linear momentum

Linear impulse

None of these

61. Substance which flows easily are

Kerosene oil

All of these

Petrol

Water

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

Become three times, its initial value

Become four times, its initial value

Remains constant

Become twice its initial value

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

None of these

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

They are always at the same point

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

Change in KE is zero

Change in KE is ½ mv²

Momentum change is mvr

Change in KE is mv²

65. The electrical forces are

Attractive

Both A and B

Repulsive

None

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

Towards the train

On the train

On himself

Away from the train

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

Limiting friction

Static friction

Rolling friction

Dynamic friction

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

All of these

Mobile oil

Thick tar

Honey

69. 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 spitting or sneezing

By jumping

By rolling your body on the surface

70. 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

22 km/s

11 km/s

5.5 km/s

71. 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

T₂ > T₁

Tension in the string always remains the same

T₁ = T₂

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

M⁰L⁰T²

ML⁰T⁰

M⁰LT²

MLT⁰

73. 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 maximum height will be same

Their time of flight will be same

Their range will be same

Their landing velocity will be same

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

Moving

Moving slowly

Moving fast

Stationary

75. Blood has a density

None of these

Lesser then water

Greater then water

Equal to water

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76. When fluid is incompressible then

Density of the fluid is constant

Flow of the fluid is straight line

Velocity of the fluid is constant

Volume of the fluid is constant

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

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

In the backward direction on both the wheels

In the forward direction on the rear wheel

In the forward direction on both the wheels

78. The concentration of red blood cells in blood is

~ 50%

~ 30%

– 40%

– 45%

79. 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

18

13

14

80. At terminal velocity, fluid friction is

None of these

Minimum

Maximum

Zero

81. Surface area is

Neither scalar nor vector

Vector

Both scalar and vector

Scalar

82. Angular momentum has the same unit as

Work x frequency

Linear momentum x time

Impulse x distance

Power x time

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

Increase the velocity of water flowing out

Increase the volume of water flowing per second

Increase the mass of water flowing per second

Avoid wastage of water

84. 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

85. 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.

√gh

√2gh

2gh

.gh

86. 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 5/12

cos¯¹ 7/13

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

Unsteady

Irregular

Steady

B and C

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

React against the rocket and push it up

Heat up the air which lifts the rocket

Push against the air

Push against the earth

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

8 N

4 N

20 N

0 N

90. 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)

19.6 m

14.7 m

4.9 m

9.8 m

91. Force of friction is present in

Liquid

All of these

Solid

Gases

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

The blood pressure increase at high altitudes

The percentage of oxygen in the air increase

The atmospheric pressure decreases there

The density of blood decreases at high altitudes

93. Drag force is given by

Newton’s law

Gauss law

Stokes law

Pascal’s law

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

Are equal to each other

Cannot be predicted

Are equal to each other in magnitude

Are not equal to each other in magnitude

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

Centrifugal force

Gravitational force

All of these

Centripetal force

96. Velocity of fluid increases where the pressure is

Constant

Changes continuously

High

Low

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

0.224 x 10¯³

0.295 x 10¯³

0.198 x 10¯³

0.301 x 10¯³

98. Bernoulli’s equation is applicable for

Turbulent flow

None of these

Laminar flow

Both laminar and turbulent flow

99. A flowing liquid possesses

P.E.

All

K.E.

Pressure Energy

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

Final velocity

Initial velocity

Instantaneous velocity

Terminal velocity

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101. Angular momentum is

Polar vector

Axial vector

At 45° angle

Scalar

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

The slower one

Both will reach simultaneously

The faster one

Depends on their mass

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

6.29 x 10¯³

6.49 x 10¯³

6.12 x 10¯³

6.18 x 10¯³

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

Very large

Small

None of these

Large

105. Unite of impulse in

Newton

Joule

Kg m/s

Kg m

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

0.064 m

64 m

640 cm

64 cm

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

300 m

200 m

100 m

400 m

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

Increases

Zero

Remains same

Decreases

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

A deuteron

An α particle

A proton

An electron

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

Change

None of these

Both

Constant

111. 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

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

Perpendicular to each other

Parallel to each other

Antiparallel to each other

Inclined to each other at an angle of 45°

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

The percentage of oxygen in the air increase

The density of blood decreases at high altitudes

The atmospheric pressure decreases there

The blood pressure increase at high altitudes

114. 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 mv

The kinetic energy changes by (1/2)mv²

The kinetic energy changes by mv²

The momentum changes by 2mv

115. Numerical value of magnitude of a physical quantity is

Inversely proportional to magnitude of the unit

Either (B) or (C)

Directly proportional to magnitude of the unit

Independent of system of units

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

M(g – a)

M(g + a)

Mg

0

117. A flowing liquid possesses

K.E.

All

Pressure Energy

P.E.

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

Electric flux

Mass flux

Magnetic flux

Both a and b

119. 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

Independent of h

Proportional to h²

Proportional to h¹⁄ ²

Proportional to h

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

¼ times

4 times

Half

Double

121. Which of the following is the smallest unit?

Meter

Fermi

Millimeter

Angstrom

122. A chimney works best when it is

Exposed to air currents

A and B

Tall

Not tall but wide

123. 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

P/2

2P

P/4

124. V = √2g(h₁ – h₂) shows the

Bernoulli’s theorem

None of these

Torricelli’s theorem

Equation of continuity

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

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

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

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

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

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

C

B

B . C

B x C

127. 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

1 m/s

10 m/s

128. 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

Linear momentum is constant

Velocity is constant

It moves in a circular path

None of these

129. At high speeds the force is no longer

None of these

Proportional

No proportion

Simply proportional

130. The mass of the block is

21,000 g

3000 g

None of these

30001 b

131. 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

5 cm/s

50 m/s

5 m/s

50 cm/s

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

High flow speed

Initially turbulent

All of these

Sound heard

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

Laminar flow

Turbulent flow

None of these

Both a and b

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

4

1

2

3

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

Variable acceleration

Variable speed and constant velocity

Constant acceleration

Constant retardation

136. 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 = 30°

None of these

θ = 90°

θ = 60°

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

4.5 x 10¯¹⁰ J

3 x 10¯¹⁹ J

4.5 x 10¯¹⁹ J

3 x 10¯¹⁰ J

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

1 : 2

1 : 1

4 : 1

1 : 4

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

0.599 x 10¯³

0.521 x 10¯³

0.564 x 10¯³

0.594 x 10¯³

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

Torricelli’s theorem

Bernoulli’s equation

None of these

Venturi relation

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

33 m

6 m

22 m

7.8 m

142. Reason of weightlessness in a satellite is

Zero gravity

Center of mass

Zero reaction force by satellite surface

None of these

143. Angular momentum is

A vector

Neither A. nor B.

Either A. or B.

A scalar

144. Which of the following quantities is a vector

Temperature

Displacement

Density

Volume

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

In a steady state

Incompressible

Non-viscous

All of these

146. 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

F/√2

Zero

E

E/2

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

Spherical

Square

Circular

Rough

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

Zero

½ Mg

Mg

2 Mg

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

0.218 m/s²

0.20 m/s²

0.027 m/s²

0.03 m/s²

150. 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

Moment of inertia depends on choice of axes

None of these

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151. Pick out the wrong pair:

Charge-coulomb

Sp. gravity-hygrometer

Temperature-thermometer

Pressure-barometer

152. Which of the following is true?

Neither momentum nor kinetic energy is conserved in inelastic collisions

Momentum is conserved in all collisions but not kinetic energy

Both momentum and kinetic energy are conserved in all collisions

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

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

Energy

Mass

Momentum

None

154. Coefficient of viscosity of honey is greater than

Milk

Petrol

Water

Alcohol

155. Dot product of two mutual perpendicular vector is:

1

∞

None of these

0

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

Electron-volt

Joule

Calorie

Watt

157. 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

8000 m

11000 m

300 m

200 m

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

Infinite

Variable

Zero

Maximum

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

Weight of body-weight of liquid displaced

Zero

Equal to weight of liquid displaced

Less than the weight of liquid displaced

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

Work

Energy

Linear momentum

Angular momentum

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

Stiffness

Strength

Ductility

Elasticity

162. Identify the pair whose dimensions are equal

Stress and energy

Force and stress

Force and work

Torque and work

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

Radial

Centrifugal

Centripetal

Tangential

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

Attractive

Both A and B

Repulsive

None

165. The blood vessels are inflated even in

Working state between heart beat

None of these

Occasionally

Relaxed states between heart beat

166. 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

9 s

5 s

3 s

7 s

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

Low

High

Zero

Constant

168. 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?

2 m/s

4 m/s

8 m/s

1 m/s

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

Equal to what is in turbulent flow

Infinite

Maximum

Minimum

170. An instrument called a sphygmomanometer measure

None of these

Blood pressure

Milk density

Density of water

171. 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

0.98 x 10¯³ Ns

0.15 x 10¯³ Ns

1.5 x 10¯³ Ns

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

tan¯¹(-P/Q)

sin¯¹(P/Q)

tan¯¹(P/Q)

cos¯¹(-P/Q)

173. 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

174. With the increase of temperature viscosity

Decrease

Remains same

Doubles

Increase

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

Striking of two glass balls

A bullet striking a bag of sand

A man jumping onto a moving cart

An electron captured by a proton

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

Force of brakes

Friction due to tyres

Force by steering wheel

The drive of the car

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

Increases

Decreases

Doubles

Does not change

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

3 and 4

2 and 3

1 and 2

4 and 5

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

Linear velocity and angular velocity

Centripetal force and radius

Moment of inertia and angular velocity

Mass and angular velocity

180. 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

9.8 m/s

98.0 m/s

39.2 m/s

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

1 J

4 J

2 J

3 J

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

Decrease for both

Decrease for liquids and increase for gases

Increase for liquids and decreases for gases

Increases for both

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

20 36 km

22.36 km

25.23 km

22.46 km

184. 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?

300 gf

500 gf

400 gf

700 gf

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

Final velocity

Terminal velocity

Initial velocity

Instantaneous velocity

186. 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

8 cm

None

1 cm

187. 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

5 : 1

1 : 5

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

Mg/2

Mg

More than 2mg

More than mg

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

The speed of the particle

The time taken in this work

The actual path taken

The height of the table

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

v/F

F/v

Fv

Fv²

191. 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

7,200 N

100,000 N

3,600 N

10,000 N

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

None of these

Decreases rapidly

Decreases

Increases

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

Av = constant

v/A = constant

None of these

A/v = constant

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

Angular momentum decreases

Moment of inertia increases

Moment of inertia decreases

Angular momentum increases

195. 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

196. 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 = t₂

t₁ = t₂/4

t₁ = t₂/2

t₁ = 4t₂

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

The object must be at rest

The acceleration of the object is zero

The object can be at rest

The object is moving at constant speed

198. The angular momentum of a body is conserved if

Torque acting on it is constant

Torque acting on it is zero

Force acting on it is zero

Force acting on it is constant

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

Pressure between the narrow gap decreases

Air velocity between the narrow gap increases

Both A and B

None

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

It will be just floating at the same point in space

It still moves with the same velocity

It will lose its velocity gradually

It will be fall down instantaneously

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

Is zero

Is equal to that of B

Is greater than that of B

Is smaller than that of B

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

Torque and work

Energy and Young’s modulus

Light year and time

Angular momentum and work

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

Density

Compressibility

Surface tension

Solar constant

204. The unit of focal power of a lens is

Watt

Kilo watt

Horse power

Diopter

205. 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

2.3

3.0

1.3

1.5

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

Increases

Remains same

First increases, then decreases

Decreases

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

Constant acceleration (g)

Constant terminal velocity

Variable speed

Variable acceleration

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

6 times

2 times

4 times

8 times

209. 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

42 km/h

37.5 km/h

10 km/h

40 km/h

210. In a uniform circular motion

Speed and acceleration change

Kinetic energy remain constant

Velocity and acceleration remain constant

Only velocity change, acceleration remain constant

211. 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 forward direction on bath the wheels

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

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

212. 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

Unequal

Roughly equal

Zero

Exactly equal

213. 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 m/s

17.5 m/s

None of these

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

Decreases

Increase

Zero

None of these

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

Law of conservation of energy

Law of conservation of mass

Law of conservation of momentum

All of these

216. The direction of the angular velocity vector is along

The outward radius

The tangent to the circular path

The axis of rotation

The inward radius

217. 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

2000

200

20,000

218. 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

5 N

12 N

8 N

2 N

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

Kinetic energy

Angular momentum

Mass

Momentum

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

55%

77%

66%

44%

221. 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

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

Decreases

Zero

Remains same

Increases

223. 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

4 times

Twice

½ of 4 cm diameter pipe

¼ times

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

None of these

Acceleration

Velocity

Force

225. 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 acceleration is constant

Its velocity is constant

Page 10 of 11

226. 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

2 ms¯²

1 ms¯²

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

None of these

Remains unchanged

Increases

Decreases

228. 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

229. Surface tension of water is reduced by adding

Detergents

Camphor

Plastic

Both A and B

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

120°

0°

60°

90°

231. The blood pressure of the person

Decreases with age

None

Remains the same

Increases with age

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

Speed

Mass

Kinetic energy

Momentum

233. 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

On the circumference of the circle

Inside the circle

Center of the circle

234. 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°

60°

90°

235. The Systolic blood pressure comes when

Vessel collapse

All of these

Cutting off the blood flow

None of these

236. 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

Equal both

Solid cylinder

Both

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

3430 J

100 J

5 J

350 J

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

Momentum

All

Energy

Mass

239. 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

240. 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

1500 m

1400 m

1300 m

241. 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

A/v = constant

v/A = constant

Av = constant

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

None of these

1 : 4 : 9

1 : 3 : 5

1 : 2 : 3

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

4 times

Half

¼ time

Double

244. 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:

11%

10%

8%

9%

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

All

Ideal fluid

Non-ideal fluid

Prefect fluid

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

36 km/h

80 km/h

40 km/h

50√2 km/h

247. A jet engine works on the principle of

Conservation of linear momentum

Conservation of angular momentum

Conservation of mass

Conservation of energy

248. Length cannot be measured by

Light year

Debye

Micron

Fermi

249. 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

First increase and then decrease

Go on decreasing

Go no increasing

250. 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

129600

36000

Page 11 of 11

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

15 N

30 N

60 N

21 N

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

Its potential energy is also doubled

Its momentum is also doubled

Its acceleration is also doubled

Its kinetic energy is also doubled

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

Variable speed

Constant acceleration (g)

Variable acceleration

Constant terminal velocity

254. S.I unit of magnetic flux is

Weber

Weber per metre⁴

Weber metre¯²

Weber per metre

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

Remain unchanged

Become zero

Increase

Decrease

256. 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

Full length of the capillary tube

0.1 m

0.2 m

0.98 m

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

9.8 N

Cannot be calculated

1 N

4.9 N

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

Maximum

Minimum

Infinite

Zero

259. 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

1.0 kg wt

Zero

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

Mass of the body

Linear kinetic energy of the body

Force in linear motion

Linear velocity of the body

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

First A and Then B

Decreases

Increases

Remains same

262. 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.

13 N, 5 N

16 N, 2 N

12 N, 6 N

10 N, 8 N

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

π

π/4

π/3

π/2

264. 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

√gh

2gh

gh

√2gh

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

Car will cover less distance before rest

Truck will cover less distance before rest

None of these

Both will cover equal distance

266. 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:

1.96 m/s²

4.9 m/s²

9.8 m/s²

None of these

267. 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

120°

90°

60°

150°

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

Volume of fluid

Density of fluid

Mass of fluid

Flow rate

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

Stick to each other

None of these

Roll upon each other

Slide upon each other

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