Q41.The relativistic form of Newton's second law of motion is
Correct answer: 2 2 mc dv F dt c v = −
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q42.If ABCD is a rectangle and AB=2a, AD=2b, then the inclination of AB of one of the principal axes at A is-
Correct answer: –1 2 2 1 3ab tan 2 2(a – b)
EnglishUP Higher Asst. Prof. 2021
Q43.Turbulence problem particularly depend on the term of the Navier Stokes equations which is the
Correct answer: diffusion term
EnglishUP Higher Asst. Prof. 2021
Q44.The Lagrangian for a charged particle in a electromagnetic field is -
Correct answer: L = T – qφ + q(ν.A)
EnglishUP Higher Asst. Prof. 2021
Q45.The constraints on bead on a uniformly rotating wire in a force free space is
Correct answer: Rheonomous
EnglishUP Higher Asst. Prof. 2021
Q46.A surface that is every where tangent to both flow velocity and vorticity is called
Correct answer: a vortex tube
Q47.Given K.E. = T = i 2 1 mr 2 and P.E. = V= i 2 2 1 r 1+ 2 c, then Hamiltonian H =?
Correct answer: Discrepancy / answer not specified in source
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q48.The Lagrange's equation of motion of simple pendulum is-
Correct answer: 2 d g sin 0 dt θ + θ = l
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q49.If A, B and C denote the moment of inertia about any three rectangular axes meeting at a given point, then which of the following is NOT correct?
Correct answer: (A+B+C) is equal to the moment of inertia about the given point.
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q50.If the Lagragian does not depend on the time explicitly, then-
Correct answer: The Hamiltonian is constant
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q51.For two systems to be equi-momental, the following conditions- I: They have same total mass II: They have same centroid III: They have same principal axes are-
Correct answer: necessary and sufficient
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q52.For the Lagrangian i i 2 2 L = ax + by – cxy, the Hamilton H is-
Correct answer: 2 y x p cxy 4a 4b + +
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q53.The equation of momental ellipsoid at the centre of elliptic plate with mass 'M' and semi axes 'a' and 'b' is-
Correct answer: 2 2 2 2 2 2 2 b x a y z (b a) constan t + + + =
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q54.A particle of mass 'm' is constrained to move in a vertical plane along a trajectory given by x=Acosθ, y=Asinθ, where 'A' is constant. The Lagrangian of the particle is-
Correct answer: 2 1 mA mgAcos 2 θ + θ i
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q55.The moment of inertia of an elliptic plate 2 2 x y + a b =1 about an axis through its centre and perpenducular to it is given by (M is the mass of the body)-
Correct answer: () 2 2 M a b 4 +
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q56.If the time of a complete oscillation of compound pendulum is 2 k 2π gh then the length of simple equivalent pendulum is-
Correct answer: 2 k h
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q57.A straight uniform rod of length 'a' can turn freely about its one end O, hangs from O vertically. The least angular velocity with which it must begin to move, so that it may perform complete revolution in a vertical plane is-
Correct answer: 6g/a
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q58.The number of degree of freedom of rigid body moving freely in space is-
Correct answer: 6
EnglishUPPSC Polytechnic Lecturer 2021 (I)
Q59.Moment of inertia of a uniform rod of length '2a' and mass 'm' about a line perpendicular to rod through the centre of mass is-
Correct answer: 2 1 ma 3
EnglishUPPSC Polytechnic Lecturer 2021(II)
Q60.If 'H' is the Hamiltonian and 'f' is any function depending on position, momenta and time, if [H, f] is the Poisson Bracket, then -
Correct answer: df f [H,f ] dt t ∂ = − ∂