ECAT Physics Fluid Dynamics Chapter Online Test

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Physics

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

Both

Solid cylinder

Solid sphere

Equal both

2. 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

3. 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

1.5 x 10¯³ Ns

0.98 x 10¯³ Ns

0.15 x 10¯³ Ns

2.5 x 10¯³ Ns

4. The unit of focal power of a lens is

Kilo watt

Diopter

Watt

Horse power

5. Surface area is

Both scalar and vector

Neither scalar nor vector

Scalar

Vector

6. 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

3 s

5 s

7 s

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

64 m

64 cm

0.064 m

640 cm

8. 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

9. The high blood pressure is

120 torr

110 torr

130 torr

100 torr

10. An instrument called a sphygmomanometer measure

Milk density

Density of water

Blood pressure

None of these

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

Zero

Low

Constant

High

12. 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:

50°

45°

40°

60°

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

All

Non-ideal fluid

Ideal fluid

Prefect fluid

14. 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°

15. Identify the pair whose dimensions are equal

Torque and work

Force and stress

Force and work

Stress and energy

16. 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

17. Reason of weightlessness in a satellite is

Zero gravity

Center of mass

None of these

Zero reaction force by satellite surface

18. Internal friction of fluid is called

Resistance

Cohesive force

Surface tension

Viscosity

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

On himself

On the train

Away from the train

Towards the train

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

None of these

Increases

Decreases

Remains unchanged

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

Unity

Unity or more

Less than unity

Unity or less

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

Change in KE is zero

Momentum change is mvr

Change in KE is ½ mv²

Change in KE is mv²

23. 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 – 5 N, F₃ = 1 N

F₁ – 3 N, F₂ – 5N, F₃ = 6 N

F₁ – 3 N, F₂ – 5N, F₃ = 15 N

24. 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

18

16

14

13

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

Mass and angular velocity

Moment of inertia and angular velocity

Linear velocity and angular velocity

Centripetal force and radius

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26. 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

9.8 m

50 m

25 m

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

1 : 4

1 : 1

1 : 2

4 : 1

28. Dot product of two mutual perpendicular vector is:

None of these

1

∞

0

29. When fluid is incompressible then

Flow of the fluid is straight line

Density of the fluid is constant

Velocity of the fluid is constant

Volume of the fluid is constant

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

All of these

Centripetal force

Centrifugal force

Gravitational force

31. 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 just floating at the same point in space

It will be fall down instantaneously

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

Not conserved

Conserved

None of these

Somewhat conserved

33. The Bernoulli’s equation is based on the

All of these

Law of conservation of energy

Law of conservation of momentum

Law of conservation of mass

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

Mg

Mg/2

More than 2mg

More than mg

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

1.014 x 10¯³

0.954 x 10¯³

1.000 x 10¯³

1.012 x 10¯³

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

Decreases

Increase

None of these

Zero

37. 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¯¹ 5/12

cos¯¹12/13

cos¯¹ 7/13

cos¯¹ 5/13

38. 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/4

P/2

P

2P

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

R

R²

(1/R)²

1/R

40. 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°

60°

90°

150°

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

16 m/s²

8 m/s²

8 radian/s²

42. 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

t₁ = t₂/2

t₁ = t₂/4

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

Variable speed and constant velocity

Variable acceleration

Constant retardation

Constant acceleration

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

Decrease for liquids and increase for gases

Increases for both

Decrease for both

Increase for liquids and decreases for gases

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

Decreases

Zero

Remains same

Increases

46. 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 smaller than molecules in the air

Surface tension of the water prevents it from

Water contains hydrogen atoms, air does not

Water molecules are larger than molecules in the air

47. 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

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

Increase the volume of water flowing per second

Avoid wastage of water

Increase the mass of water flowing per second

Increase the velocity of water flowing out

49. Ball pen functions on the principle of

Viscosity

Surface tension

Gravitational force

Boyle’s law

50. 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

None of these

Linear acceleration

No acceleration

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51. 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

12 N, 6 N

16 N, 2 N

13 N, 5 N

52. Blood has a density

Lesser then water

Greater then water

Equal to water

None of these

53. 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

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

Linear kinetic energy of the body

Linear velocity of the body

Mass of the body

Force in linear motion

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

π/2

π

π/4

π/3

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

Half

¼ times

4 times

Double

57. A flowing liquid possesses

All

K.E.

P.E.

Pressure Energy

58. 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)

1.0 kg wt

2.0 kg wt

Zero

0.5 kg wt

59. Wb/m² is equal to

Henry

Tesla

Dynes

Watt

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

Flow rate

Density of fluid

Mass of fluid

Volume of fluid

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

Initially turbulent

Sound heard

High flow speed

All of these

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

Friction due to tyres

The drive of the car

Force by steering wheel

Force of brakes

63. The Systolic blood pressure comes when

Cutting off the blood flow

None of these

All of these

Vessel collapse

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

Equal to what is in turbulent flow

Infinite

Minimum

Maximum

65. Length cannot be measured by

Light year

Fermi

Micron

Debye

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

Both have the same momentum

Light object

Heavy object

Data is not sufficient

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

Size of the body

Radius of the body

Square of the diameter of the body

Diameter of the body

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

Constant acceleration (g)

Variable acceleration

Constant terminal velocity

Variable speed

69. 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

¼ times

½ of 4 cm diameter pipe

4 times

70. 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)

cos¯¹(-P/Q)

tan¯¹(-P/Q)

71. In a uniform circular motion

Kinetic energy remain constant

Only velocity change, acceleration remain constant

Speed and acceleration change

Velocity and acceleration remain constant

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

A bullet striking a bag of sand

Striking of two glass balls

A man jumping onto a moving cart

An electron captured by a proton

73. 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

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

Pressure, stress

Work, energy

Force, impulse

Velocity, speed

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

Speed

Kinetic energy

Mass

Momentum

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76. The blood vessels are inflated even in

Relaxed states between heart beat

Occasionally

None of these

Working state between heart beat

77. Unite of impulse in

Kg m

Kg m/s

Newton

Joule

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

Roll upon each other

Slide upon each other

Stick to each other

None of these

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

Is smaller than that of B

Is zero

Is greater than that of B

Is equal to that of B

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

Energy

Mass

Momentum

All

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

Acceleration

None of these

Velocity

Force

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

Unsteady

B and C

Steady

Irregular

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

By rolling your body on the surface

By running on the plane

By spitting or sneezing

By jumping

84. Which of the following is the smallest unit?

Fermi

Angstrom

Millimeter

Meter

85. 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 density of blood decreases at high altitudes

The atmospheric pressure decreases there

86. The atmosphere is held to the earth by

Winds

Clouds

The rotation of earth

Gravity

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

Does not change

Doubles

Increases

Decreases

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

Cannot be calculated

1 N

9.8 N

4.9 N

89. 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

Velocity

Total energy

Kinetic energy

Momentum

90. 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

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

C

B x C

B

B . C

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

Twice the initial value

Four times the initial value

Thrice the initial value

Same as the initial value

93. Venturi relation is used measure

Pressure of the liquid

Height of the pipe

Speed of liquid flow

Density of the liquid

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

Moves in different direction

Moves along the same path as

None of these

Slowly moves in one direction

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

Energy

Mass

Angular momentum

Linear momentum

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

In the forward direction on the rear wheel

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

In the forward direction on both the wheels

In the backward direction on both the wheels

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

25.23 km

20 36 km

22.46 km

22.36 km

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

Surface energy

Bernoulli’s equation

Equation of continuity

Magnus effect

99. 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 not equal to each other in magnitude

Are equal to each other

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

Stiffness

Strength

Elasticity

Ductility

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

Zero

Low

High

Constant

102. 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 a function of the angle

Still 76 cm

76 cm plus the angle

76 cm minus the angle

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

Instantaneous velocity

Terminal velocity

Initial velocity

Final velocity

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

4 times

8 times

2 times

6 times

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

Moment of inertia increases

Moment of inertia decreases

Angular momentum increases

Angular momentum decreases

106. 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

Tension in the string always remains the same

T₂ > T₁

T₁ > T₂

T₁ = T₂

107. The low blood pressure is known as

Diastolic

Low blood pressure

None of these

Systolic

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

Venturi relation

Bernoulli’s equation

None of these

Torricelli’s theorem

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

44%

66%

77%

55%

110. 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

111. 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

112. A jet engine works on the principle of

Conservation of linear momentum

Conservation of mass

Conservation of angular momentum

Conservation of energy

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

Decreases rapidly

Increases

Decreases

None of these

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

Decrease

Increase

Remain unchanged

Become zero

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

4.9 N

9.8 N

Cannot be calculated

1 N

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

Constant

Both

Change

None of these

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

4.5 x 10¯¹⁰ J

3 x 10¯¹⁹ J

3 x 10¯¹⁰ J

4.5 x 10¯¹⁹ J

118. 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 both 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

119. 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

50√2 km/h

40 km/h

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

Weight of body-weight of liquid displaced

Less than the weight of liquid displaced

Equal to weight of liquid displaced

Zero

121. 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

10 km/h

40 km/h

37.5 km/h

42 km/h

122. Pick out the wrong pair:

Sp. gravity-hygrometer

Pressure-barometer

Charge-coulomb

Temperature-thermometer

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

First increases, then decreases

Remains same

Increases

Decreases

124. V = √2g(h₁ – h₂) shows the

Torricelli’s theorem

None of these

Equation of continuity

Bernoulli’s theorem

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

All of these

Law of conservation of mass

Law of conservation of energy

Law of conservation of momentum

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126. 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

90°

120°

60°

127. 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

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

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

Constant acceleration (g)

Variable speed

Variable acceleration

Constant terminal velocity

129. Swimming is based on the principle of

Newton’s 2nd law

Newton’s 3rd law

Newton’s 1st law

All

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

Surface tension of the gas

Adhesion between the gas molecules and the container

Collision between the gas molecules and the container

Cohesion between the gas molecules and the container

131. The concentration of red blood cells in blood is

– 40%

– 45%

~ 30%

~ 50%

132. 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?

10 m/s

1 m/s

0.01 m/s

0.1 m/s

133. With the increase of temperature viscosity

Increase

Doubles

Decrease

Remains same

134. 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

8 N

20 N

4 N

135. 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 landing velocity will be same

Their maximum height will be same

Their range will be same

Their time of flight will be same

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

Half

4 times

Double

¼ time

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

1980 J

968 J

98 J

None of these

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

The acceleration of the object is zero

The object is moving at constant speed

The object can be at rest

The object must be at rest

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

6.29 x 10¯³

6.49 x 10¯³

6.18 x 10¯³

6.12 x 10¯³

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

Both a and b

Turbulent flow

None of these

Laminar flow

141. Stoke’s law is applicable to

Motion through viscous medium

Motion through horizontal surface

Motion through non-resistive medium

Motion through free space

142. 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?

700 gf

300 gf

500 gf

400 gf

143. 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)

14.7 m

9.8 m

19.6 m

4.9 m

144. The unit of inductance is equivalent to

Volt/ampere x second

Volt x second/ampere

Ampere/volt x second

Volt x ampere/second

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

Angular momentum

Power

Momentum

Energy

146. 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 cm/s

5 cm/s

5 m/s

50 m/s

147. Force of friction is present in

Gases

All of these

Liquid

Solid

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

Weight in air

Weight in water

Weight in the liquid

Density

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

4 m/s

None of these

2 m/s

1 m/s

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

Action of gravity

(h₁ – h₂) and falling under gravity

None of these

h₁ – h₂

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151. The mass of the block is

3000 g

21,000 g

30001 b

None of these

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

None

Attractive

Both A and B

Repulsive

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

1500 m

1200 m

1400 m

1300 m

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

Velocity

Acceleration

Centripetal force

Kinetic energy

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

4 J

1 J

2 J

3 J

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

None of these

When a net external impulse is acting upon the system

When a net eternal torque is acting upon the system

When net external force is acting upon the system

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

Work

Linear momentum

Energy

Angular momentum

158. 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

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

Twice

Four times

Thrice

Once

160. Bernoulli’s equation is applicable for

Laminar flow

Both laminar and turbulent flow

None of these

Turbulent flow

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

Momentum

Mass

Angular momentum

Kinetic energy

162. 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

None of these

17 m/s

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

Square

Spherical

Circular

Rough

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

Mixed

Turbulent

None of these

Laminar

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

Small

None of these

Very large

Large

166. 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

P²t²/m

P²t²/2m

P²t²/3m

Pt/2m

167. The rectangular components of force 5 dyne are

2 and 3 dyne

2.5 and 25 dyne

3 and 4 dyne

1 and 2 dyne

168. 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

129600

360000

36000

169. The blood pressure of the person

None

Remains the same

Increases with age

Decreases with age

170. 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

1.5

1.3

3.0

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

Energy and Young’s modulus

Angular momentum and work

Light year and time

Torque and work

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

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

None of these

Center of mass changes but center of gravity is always same

They are always at the same point

173. The direction of the angular velocity vector is along

The axis of rotation

The inward radius

The outward radius

The tangent to the circular path

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

Become twice its initial value

Become four times, its initial value

Remains constant

Become three times, its initial value

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

30 N

15 N

60 N

21 N

Page 8 of 11

176. 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:

22 km/s

16.5 km/s

11 km/s

5.5 km/s

177. 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

2W

Zero

W/2

178. 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

3.2 joule

2.8 joule

4.4 joule

3.8 joule

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

R

(3/2)R

2R

4R

180. The angular momentum of a body is conserved if

Torque acting on it is zero

Force acting on it is zero

Torque acting on it is constant

Force acting on it is constant

181. 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

Between 3 and 4 dyne

More than 4 dynes

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

Inside the circle

Center of the circle

Outside the circle

On the circumference of the circle

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

3 : 1

1 : 1

1 : 3

2 : 1

184. Which of the following quantity is dimensionless?

Gravitational constant

Power of lens and gas constant

Plank’s constant

None of these

185. At high speeds the force is no longer

No proportion

Proportional

Simply proportional

None of these

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

Avoid wastage of water

Increase the volume to water flowing per second

Increase the mass of water flowing per second

Increase the volume to water flowing out

187. 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

100 m

200 m

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

Fv²

v/F

F/v

Fv

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

Remains same

First A and Then B

Increases

Decreases

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

Its kinetic energy is also doubled

Its acceleration is also doubled

Its potential energy is also doubled

Its momentum is also doubled

191. 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 moves in straight line

Its kinetic energy is constant

Its acceleration is constant

Its velocity is constant

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

Electric flux

Both a and b

Mass flux

Magnetic flux

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

Moving

Moving fast

Stationary

Moving slowly

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

Dynamic friction

Limiting friction

Static friction

Rolling friction

195. 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

196. At terminal velocity, fluid friction is

Maximum

None of these

Minimum

Zero

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

v/A = constant

None

Av = constant

A/v = constant

198. Which of the following quantities is a vector

Temperature

Displacement

Volume

Density

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

An α particle

A proton

An electron

A deuteron

200. 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

10,000 N

3,600 N

7,200 N

100,000 N

Page 9 of 11

201. A chimney works best when it is

Tall

Not tall but wide

Exposed to air currents

A and B

202. 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?

4 m/s

2 m/s

1 m/s

8 m/s

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

Angular velocity

Mass distribution

Axis of rotation

Mass of object

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

0.295 x 10¯³

0.224 x 10¯³

0.301 x 10¯³

0.198 x 10¯³

205. 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

Zero

E

F/√2

206. 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

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

Maximum

Variable

Zero

Infinite

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

ML⁰T⁰

MLT⁰

M⁰L⁰T²

M⁰LT²

209. 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

210. Surface tension of water is reduced by adding

Both A and B

Plastic

Detergents

Camphor

211. The low blood pressure is

78 – 809 torr

79 – 80 torr

75 – 80 torr

70 – 80 torr

212. 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 earth

Heat up the air which lifts the rocket

Push against the air

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

Both A and B

Pressure between the narrow gap decreases

Air velocity between the narrow gap increases

None

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

Final velocity

Instantaneous velocity

Initial velocity

Terminal velocity

215. Velocity of fluid increases where the pressure is

Constant

High

Low

Changes continuously

216. 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:

1 : 1

2 : 5

5 : 1

1 : 5

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

3 and 4

1 and 2

2 and 3

4 and 5

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

0.521 x 10¯³

0.564 x 10¯³

0.594 x 10¯³

0.599 x 10¯³

219. Substance which flows easily are

Petrol

Kerosene oil

All of these

Water

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

Centripetal

Centrifugal

Radial

Tangential

221. Coefficient of viscosity of honey is greater than

Water

Alcohol

Petrol

Milk

222. 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:

10%

8%

9%

11%

223. Numerical value of magnitude of a physical quantity is

Directly proportional to magnitude of the unit

Independent of system of units

Inversely proportional to magnitude of the unit

Either (B) or (C)

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

Zero

Remains same

Increases

Decreases

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

All of these

Incompressible

In a steady state

Non-viscous

Page 10 of 11

226. 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

200

2000

20,000

20

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

½ Mg

Zero

2 Mg

Mg

228. 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

None of these

Linear momentum is constant

It moves in a circular path

Velocity is constant

229. 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 h¹⁄ ²

Proportional to h

Proportional to h²

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

Solar constant

Compressibility

Density

Surface tension

231. 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:

4.9 m/s²

None of these

9.8 m/s²

1.96 m/s²

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

The ground on the cart

The horse on the ground

The horse on the cart

The ground on the horse

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

1 : 2 : 3

1 : 4 : 9

None of these

1 : 3 : 5

234. 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

Go on decreasing

First increase and then decrease

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

The height of the table

The actual path taken

The time taken in this work

The speed of the particle

236. Which of these statements is not correct?

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

Moment of inertia does not depend on mass of body

None of these

Moment of inertia depends on choice of axes

237. 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°

θ = 90°

None of these

θ = 60°

238. Angular momentum is

A vector

A scalar

Neither A. nor B.

Either A. or B.

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

The ball had covered more than half the distance

The ball had covered exactly half the distance

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

240. 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

N

Zero

0.5 N

0.05 N

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

Mg

0

M(g – a)

M(g + a)

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

Calorie

Joule

Electron-volt

Watt

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

Kinetic energy increases

Momentum decreases

Kinetic energy decreases

Momentum increases

244. 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 west to east

To fall at an angle going from east to west

To fall vertically down

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

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

None

Momentum

Energy

Mass

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

22 m

7.8 m

33 m

6 m

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

All of these

Thick tar

Honey

Mobile oil

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

120°

90°

0°

60°

249. Angular momentum has the same unit as

Power x time

Impulse x distance

Work x frequency

Linear momentum x time

250. 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

300 m

8000 m

11000 m

Page 11 of 11

251. 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

Av = constant

A/v = constant

v/A = constant

252. A flowing liquid possesses

K.E.

P.E.

All

Pressure Energy

253. 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

5 J

100 J

350 J

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

0.027 m/s²

0.20 m/s²

0.03 m/s²

0.218 m/s²

255. 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

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

None of these

Force

Linear momentum

Linear impulse

257. The electrical forces are

Both A and B

Attractive

None

Repulsive

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

The force is always away from the center

Force and displacement are perpendicular to each other

There is no net force

There is no displacement

259. Drag force is given by

Pascal’s law

Gauss law

Newton’s law

Stokes law

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

Truck will cover less distance before rest

Both will cover equal distance

Car will cover less distance before rest

None of these

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

Zero

Minimum

Infinite

Maximum

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

Energy

Momentum

Mass

Fluid

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

The density of blood decreases at high altitudes

The atmospheric pressure decreases there

The percentage of oxygen in the air increase

The blood pressure increase at high altitudes

264. Which of the following is true?

Neither momentum nor kinetic energy is conserved in inelastic collisions

Both momentum and kinetic energy are conserved in all collisions

Momentum is conserved in all collisions but not kinetic energy

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

265. 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

1 cm

8 cm

2 cm

None

266. Angular momentum is

Scalar

Axial vector

Polar vector

At 45° angle

267. 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:

2 x 10² cm³

None of these

1 x 10² cm³

1.763 x 10² cm³

268. S.I unit of magnetic flux is

Weber metre¯²

Weber per metre

Weber

Weber per metre⁴

269. 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

0.2 m

Full length of the capillary tube

0.98 m

0.1 m

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