Q21. The distance s of a particle moving in a straight line in terms of time t is given by: s = a cos (nt + ϵ), where a, n, t are constant. Then the retardation is proportional to:
A s2
B 1/s
C 2 1 s
D s
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Correct answer: s
Q22. If a particle thrown vertically upwards takes t sec to rise to a height h and t' sec in the subsequent time to reach the ground again, then:
A 1 h = gtt 2 ′
B ()2 1 h = g t t 2 ′ +
C () 1 h = g t t 2 ′ +
D () ()2 1 h = u t + t g t t 2 ′ ′ − +
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Correct answer: 1 h = gtt 2 ′
Q23. For a rectilinear motion of a particle, if an impulse I changes its velocity from u to v and E is the change of kinetic energy, then:
A u + 2v E = I 3
B 2u +3v E = I 5
C u + v E = I 2
D 3u + 2v E = I 5
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Correct answer: u + v E = I 2
Q24. If a particle describes a curve whose equation is 2 a = θ r + b under a force to the pole, then the law of force (p) is–
A 3 2a + r P r ∝
B 3 2r + a P r ∝
C 2 2a + r P r ∝
D 3 a P r ∝
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Correct answer: 3 2r + a P r ∝
Q25. If a particle moves in a straight line according to the law x = a sin(μ μ μt + ϵ), then the velocity v is related by:
A v2 = µ(x2 – a2)
B v2 = µ2 (a2 – x2)
C v2 = µ(a2 – x2)
D v2 = µ2 (x2 – a2)
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Correct answer: v2 = µ2 (a2 – x2)
Q26. If the stream function is given by ψ ψ ψ = 6x + 12y, then the speed of flow is given by:
A –1/180ms
B 1/170ms
C –1/3 2ms
D –1/0.5ms
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Correct answer: –1/180ms
Q27. Digital circuit can be made by the repeated use of which gate?
A OR
B None of the given options
C NOT
D NAND
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Correct answer: NAND
Q28. A solid homogeneous cone of height 'h' and semi-vertical angle α oscillates about a diameter of its base. Then the length of the simple equivalent pendulum is:
A () 2 h 2 5tan 5 + α
B () 2 h 2 3tan 5 + α
C () 2 h 2 3tan 3 + α
D () 2 h 2 5tan 2 + α
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Correct answer: () 2 h 2 3tan 5 + α
Q29. Consider variable µ that satisfies the equation 2 d µ + µ = 2kcosθ dθ and the conditions: (i) µ has some value when π θ = ± 2 (ii) ∫ π 2 0 µdθ = 0 The value of this variable µ is given by: (for arbitrary constant 'k')
A () k sin cos µ = θ + θ
B () k sin cos µ = θ+ θ
C () k sin – cos µ = θ
D () k sin – cos µ = θ
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Correct answer: () k sin – cos µ = θ
Q30. The moment of inertia of a uniform thin rod of mass 'M' and length 'L' about a perpendicular axis of rotation at its end is:
A 2 1 ML 8
B 2 1 ML 2
C 2 1 ML 3
D 2 1 ML 4
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Correct answer: 2 1 ML 3
Q31. If P and Q are two non-intersecting forces whose directions are perpendicular, then the ratio of distance of the central axis from their lines of action is represented as:
A Q2: 2P2
B 2P2: Q2
C Q2: P2
D P2: Q2
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Correct answer: Q2: P2
Q32. A rough uniform board of mass 'm' and length 2a rests on a smooth horizontal plane. A man of mass 'M' walks on it from one end to the other. The distance through which the board moves in this time is:
A () 3Ma m M / +
B () 3Ma m 2M / +
C () 2Ma m M / +
D () Ma m M / +
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Correct answer: () 2Ma m M / +
Q33. Two ends A and B of a rod of length 20cm have the temperature at 40° ° °C and 90° ° °C respectively until steady state prevails. After the steady state has prevailed, the temperature at the ends A and B are changed to 45° ° °C and 95° ° °C respectively. The temperature distribution in the root at time t is given by () ∑ 2 k(2m–1π – t 20 m=1 2m –1 πx 20 µ x,t = Ax + B + sin.e 2m –1 π 20 ∞ where:
A 3 A,B 42 2 =
B 5 A 45,B 2 =
C 5 3 A,B 2 2 =
D 5 A,B 45 2 =
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Correct answer: 5 A,B 45 2 =
Q34. The area under the curve given by the polar co- ordinates r = f (ⱷ) is given by:
A ∫(r2/) dⱷ
B 3 r dr 2 ∫
C 2∫(r2/) dⱷ
D 2 r 2 ∫ dⱷ
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Correct answer: 2 r 2 ∫ dⱷ
Q35. The moment of inertia of an ellipse of mass 'M' and semi axes a and b about a tangent is: (where p is the perpendicular from the centre on the tangent.)
A 2 5M p 4
B 2 5M p 6
C 2 5M p 2
D 2 5M p 3
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Correct answer: 2 5M p 4
Q36. Two equal uniform rods AB and AC, each of length 2b, are freely joined at A and are rested on a smooth vertical circle of radius a. If 2θ is the angle between them, then:
A a sin3 θ = b cosθ
B b sin2 θ = a cosθ
C a sin2 θ = b cosθ
D b sin3 θ = a cosθ
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Correct answer: b sin3 θ = a cosθ
Q37. A particle starts from origin. The components of its velocity parallel to the axes of coordinator at time 't' are 2t + 3 and 4t. Then the path travelled by the particle is given by:
A 4x2 – y2 – 4xy + 18y = 0
B x2 + y2 + xy – 12y = 0
C 3x2 + y2 + 4xy – 18y = 0
D 4x2 + y2 – 4xy – 18y = 0
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Correct answer: 4x2 + y2 – 4xy – 18y = 0
Q38. A solid frustum of a paraboloid of revolution of height 'h' and latus rectum 4a rests with its vertex on the vertex of a paraboloid of revolution whose latus rectum is 4b. Then the equilibrium is stable if:
A 3ab h a b < +
B 2ab h a b < +
C ab h a b > +
D 3ab h a b > +
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Correct answer: 3ab h a b < +
Q39. The Hamiltonian of a particle moving in one dimension whose Lagrangian is given by i 2 x L = – V(x) 2x is
A 2 P H = – V(x) 2x
B 2 x H = + V(x) 2 i
C 2 x H = + V(x) 2x i
D 2 1 H = xP + V(x) 2
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Correct answer: 2 x H = + V(x) 2x i
English UPPSC GDC 2021 UPPSC Polytechnic Lecturer 2021(II)
Q40. Let (p, q) and (P, Q) be two pairs of canonical variables. The transformation P = qα sin (β p) and Q = qα cos (β p) is canonical for
A 1 2, 2 α = β =
B 2, 2 α = β =
C 1, 2 2 α = β =
D 1 1 α = β =
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Correct answer: 1, 2 2 α = β =