০০। A body in motion will be subjected to coriolis acceleration when that body is
ক) in plane rotation with variable velocity
খ) in plane translation with variable velocity
গ) in plane motion which is a resultant of plane translation and rotation
ঘ) restrained to rotate while sliding over another body
০১। A body is said to be under forced vibrations, when
ক) there is a reduction in amplitude after every cycle of vibration
খ) no external force acts on a body, after giving it an initial displacement
গ) a body vibrates under the influence of external force
ঘ) none of the above
০২। A body is said to vibrate with simple harmonic motion if its acceleration is proportional to the distance from the mean position.
ক) Yes
খ) No
০৩। A body of weight W is required to move up the rough inclined plane whose angle of inclination with the horizontal is α. The effort applied parallel to the plane is given by (where μ = tan φ = Coefficient of friction between the plane and the body)
ক) P = W tan α
খ) P = W tan (α + φ)
গ) P = W (sin α + μ cos α)
ঘ) P = W (cos α + μ sin α)
০৪। A chain consisting of four links and four joints is called a kinematic chain.
ক) Yes
খ) No
০৫। A combination of kinematic pairs, joined in such a way that the relative motion between the links is completely constrained, is called a
ক) structure
খ) mechanism
গ) kinematic chain
ঘ) inversion
০৬। A disc is a spinning with an angular velocity ω rad/s about the axis of spin. The couple applied to the disc causing precession will be (where I = Mass moment of inertia of the disc, and ωP = Angular velocity of precession of the axis of spin)
ক) Iω2
খ) Iω2
গ) IωωP
ঘ) IωωP
০৭। A disturbing mass m1 attached to the rotating shaft may be balanced by a single mass m2 attached in the same plane of rotation as that of m1, such that (where r1 and r2 are the radii of rotation of m1 and m2 respectively)
ক) m1r2 = m2r1
খ) m1r1 = m2r2
গ) m1m2 = r1r2
ঘ) none of these
০৮। A fixed gear having 200 teeth is in mesh with another gear having 50 teeth. The two gears are connected by an arm. The number of turns made by the smaller gear for one revolution of arm about the centre of bigger gear is
ক) 2
খ) 3
গ) 4
ঘ) 5
০৯। A flywheel is fitted to the crankshaft of an engine having W as the amount of indicated work per revolution and permissible limits of coefficient of fluctuation of energy and speed as CE and CS respectively. The kinetic energy of the flywheel is given by
ক)
খ)
গ)
ঘ)
১০। A flywheel is used to control the mean speed of an engine caused by the variations in load.
ক) Correct
খ) Incorrect
১১। A force acting in the opposite direction to the motion of the body is called force of friction.
ক) True
খ) False
১২। A friction circle is a circle drawn when a journal rotates in a bearing. Its radius depends upon the coefficient of friction and the
ক) magnitude of the forces on journal
খ) angular velocity of journal
গ) clearance between journal and bearing
ঘ) radius of journal
১৩। A governor is said to be isochronous when range of speed is zero for all radii of rotation of the balls within the working range, neglecting friction.
ক) Yes
খ) No
১৪। A governor is said to be stable, if the
ক) radius of rotation of balls increases as the equilibrium speed decreases
খ) radius of rotation of balls decreases as the equilibrium speed decreases
গ) radius of rotation of balls increases as the equilibrium speed increases
ঘ) radius of rotation of balls decreases as the equilibrium speed increases
১৫। A Hartnell governor has its controlling force (Fc) given by Fc = ar + b, where r is the radius of rotation and a and b are constants. The governor becomes isochronous when
ক) a is + ve and b = 0
খ) a = 0 and b is + ve
গ) a is + ve and b is - ve
ঘ) a is + ve and b is also + ve
১৬। A Hartnell governor is a
ক) dead weight governor
খ) pendulum type governor
গ) spring loaded governor
ঘ) inertia governor
১৭। A kinematic chain is known as a mechanism when
ক) none of the links is fixed
খ) one of the links is fixed
গ) two of the links are fixed
ঘ) none of these
১৮। A link or element need not to be a rigid body, but it must be a resistant body.
ক) Agree
খ) Disagree
১৯। A machine mounted on a single coil spring has a period of free vibration of tp . If the spring is cut into four equal parts and placed in parallel and the machine is mounted on them, then the period of free vibration of the new system will become