461. The critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in
transverse vibrations
torsional vibrations
longitudinal vibrations
all of these
✅ The correct answer is option A.
Theory of machines MCQs
462. In a four stroke I.C. engine, the turning moment during the compression stroke is
positive throughout
negative throughout
positive during major portion of the stroke
negative during major
✅ The correct answer is option B.
463. A governor is said to be stable, if the
radius of rotation of balls increases as the equilibrium speed decreases
radius of rotation of balls decreases as the equilibrium speed decreases
radius of rotation of balls increases as the equilibrium speed increases
radius of rotation of
✅ The correct answer is option C.
464. For the isochronous Porter governor, the controlling force curve is a straight line passing through the origin.
Correct
Incorrect
✅ The correct answer is option A.
466. A point B on a rigid link AB moves with respect to A with angular velocity ω rad/s. The total acceleration of B with respect to A will be equal to
vector sum of radial component and coriolis component
vector sum of tangential component and coriolis component
vector sum of radial component and tangential component
vector difference of r
✅ The correct answer is option C.
467. A rigid body, under the action of external forces, can be replaced by two masses placed at a fixed distance apart. The two masses form an equivalent dynamical system, if
the sum of the two masses is equal to the total mass of body
the centre of gravity of the two masses coincides with that of the body
the sum of mass moment of inertia of the masses about their centre of gravity is equal to the mass moment of inertia of the body
all of the above
✅ The correct answer is option D.
468. The velocity of a flat-faced follower when it has contact with the flank of a circular arc cam, is given by
ωR cos θ
ω(R – r1)cos θ
ω(R – r1)sin θ
ωr1 sin θ
✅ The correct answer is option C.
470. Which of the following is an inversion of a double slider crank chain?
Oldham’s coupling
Elliptical trammel
Scotch yoke mechanism
all of these
✅ The correct answer is option D.