English UPPSC Polytechnic Lecturer 2021(II)
Q81. Equation of continuity in cartesian coordinates is -
A D u v w 0 Dt x y z ρ ∂ ∂ ∂ + ρ + + = ∂ ∂ ∂
B u v w 0 t x y z ∂ρ ∂ ∂ ∂ + ρ − − = ∂ ∂ ∂ ∂
C u v w 0 t x y z ∂ρ ∂ ∂ ∂ − ρ − − = ∂ ∂ ∂ ∂
D None of these Where D u v w Dt t x y z ∂ ∂ ∂ ∂ ≡ + + + ∂ ∂ ∂ ∂
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Correct answer: D u v w 0 Dt x y z ρ ∂ ∂ ∂ + ρ + + = ∂ ∂ ∂
English UPPSC Polytechnic Lecturer 2021(II)
Q82. If φ = A (x2 – y2) represents a possible flow phenomenon, then the stream function is-
A ψ = Ax + C
B ψ = 2Axy + C
C ψ = A x y + C
D ψ = Ax2 y2 + C
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Correct answer: ψ = 2Axy + C
English UPPSC Polytechnic Lecturer 2021(II)
Q83. If the speed of fluid is everywhere the same, the streamlines are –
A Circular
B Parabolic
C Straight lines
D None of these
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Correct answer: Straight lines
Q84. If a normal at any point P of a common catenary meets the directrix at Q & ρ is the radius of curvature of catenary at P then PQ is equal to–
A ρ
B c sec ψ
C c tan ψ
D c 2 sec ψ
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Correct answer: ρ
Q85. A sphere after collision with a plane vertically downwards with velocity 20 cm per second returns upwards with velocity 4 cm/second then the value of the coefficient of restitution e is–
A 1/2
B 1/3
C 1/4
D 1/5
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Correct answer: 1/5
Q86. A hemisphere rests in equilibrium on a sphere of equal radius. If the flat surface of the hemisphere rests on the sphere then this equilibrium is –
A Stable
B Unstable
C Neutral
D None of the above
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Correct answer: Stable
Q87. Two uniform solid spheres composed of the same material and having their radii 6 cm and 3 cm respectively are firmly united. The distance of the centre of gravity of the whole body from the centre of the larger sphere is –
A 4 cm
B 3 cm
C 2 cm
D 1 cm
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Correct answer: 1 cm
Q88. A stone just clears a wall of height 75 meters situated at a distance 150 meter and goes in horizontal direction, then the angle of projection is-
A 30º
B 60º
C 45º
D 75º
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Correct answer: 45º
Q89. The work done by the force () () ∧ ∧ 2 2 F = – y + i– 2 y + y j x x x, displacing a particle in the xy plane from (0, 0) to (1, 1) along the parabola y2 = x, is
A 2
B 3
C 1/2
D none of these
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Correct answer: none of these
Q90. The moment of inertia of a circular ring of radius a and mass M about an axis through the centre perpendicular to its plane is–
A 2 1 Ma 2
B Ma2
C 2 Ma 3
D 2 4 Ma 3
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Correct answer: Ma2
Q91. The Cartesian equation of the common catenary is -
A y2 = c2 + x2
B y = c cosh c x
C y = c secx
D y = c tan hx
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Correct answer: y = c cosh c x
Q92. The area lying between line y = x, x axis and ordinates x = 0 and x = 2 is revolved about x axis. The centre of gravity of the solid thus generated is at the following point.
A 1,0 2
B 3,0 2
C 3,0 4
D 1,0 4
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Correct answer: 3,0 2
Q93. Moment of inertia of a hollow sphere about a diameter whose mass is M and radius a, is
A M. 2 2a 3
B M. 2 2a 5
C M. 2 a 4
D M. 2 a 3
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Correct answer: M. 2 2a 3
Q94. A particle moves along the curve x = t3 –2, y = t2 + t, z = 2t + 1. The component of its acceleration at t =1 in the direction i– j k ∧ ∧ ∧ + is-
A 4
B 4 3
C 4/3
D 2
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Correct answer: 4/3
Q95. If the horizontal range of a projectile is equal to its gained maximum height then its angle of projection is –
A 4/π
B tan–1/2
C tan–1/4
D 3/π
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Correct answer: tan–1/4
Q96. A particle is moving along a plane curve with uniform speed v. Its angular velocity θ ɺ about a point O in the plane, when it is at some point P of its path, is
A Inversely proportional to OP2
B Proportional to OP2
C Proportional to OP
D Inversely proportional to OP
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Correct answer: Inversely proportional to OP
English UPPSC GIC 2021 UPPSC Ashram Paddhati 2021
Q97. If the radial and transverse velocities of a particle are always proportional to each other, then the particle will describe-
A a straight line
B a parabola
C a hyperbola
D an equiangular spiral
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Correct answer: an equiangular spiral
Q98. If the horizontal range of a projectile is four times of its maximum height, then the angle of projection will be
A 30º
B 45º
C 60º
D None of these
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Correct answer: 45º
Q99. A body of mass m falls from rest through a height 1 km under gravitational acceleration 10 m/s2 and is then brought to rest by penetrating through a depth 200 m into sand. The average deceleration of the body during penetration into sand is-
A 50 m/s2
B 20 m/s2
C 250 m/s
D 125 m/s2
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Correct answer: 50 m/s2
English UPPSC GIC 2021 UPPSC Ashram Paddhati 2021
Q100. A uniform beam of length '2a' rests in equilibrium against a smooth vertical wall upon a peg at a distance 'b' from the wall. The inclination of the beam to the vertical is-
A 2/ 3 1 b cos a −
B 1/ 3 1 a 2cos b −
C 1/ 3 1 b sin a −
D None of the above
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Correct answer: 1/ 3 1 b sin a −