In a pin jointed mechanism, the line of thrust on a link is
A.tangential to the friction circles at the ends
B.along the friction axis
C.inclined to axis of link by an angle ?, known as angle of friction
D.All the above
Category: Theory of Machines Mcqs
An axial flow fan balanced at one speed often exhibits substantial vibrational effects when operated at other speeds, mainly due to
A.Secondary critical speed effect
B.Primary critical speed effect
C.Unbalanced parts of fan
D.Aerodynamic unbalance
E.Vibration in air
The sense of tangential acceleration of a link
A.Is the same as that of velocity
B.Is opposite to the velocity
C.Could be either the same or opposite to velocity
D.Is always in a plane perpendicular to the plane of motion
E.None of the above
Bearing suitable for fluctuating loads is
A.Bush bearing
B.Sleeve bearing
C.Ball bearing
D.Roller bearing
E.Needle roller bearing
The Ackermann steering gear consists of a four bar mechanism with
A.Only one pair turning and three paris sliding
B.Only two pairs turning and low pairs sliding
C.Only three pairs turning and one pair sliding
D.All four pairs turning
E.All four pairs sliding
The rotor of a ship rotates in anticlock wise direction when viewed from the bow end and the ship takes a left turn. The effect of gyroscopic couple on the ship is
A.to lower the bow and raise the stern
B.to raise the bow and lower then stern
C.to roll the ship slightly clockwise when viewed fro bow end
D.None of the above
In case of gears the pressure angle is
A.The angle between the line of action and the common tangent to the pitch surface in the plane of rotation
B.The angle between the normal to the point of contact and the shaft axis
C.The angle between the normal to dedendum at the path point and tangent to the dedendum at the path point and tangent to the dedendum at the same point
D.The angle of obliquity between the tangent drawn at the point of contact of the two mating gears
E.None of the above
In Iocomotives, swaying couple is caused due to
A.Unbalanced parts of the primary forces acting at a distance between the line of stroke of the cylinders
B.Unbalanced part of the secondary forces acting at a distance between the line of stroke of the cylinders
C.Vertical unbalanced primary forces acting in the plane of the wheels
D.Vertical unbalanced primary forces acting in the plane of the wheels
E.Horizontal unbalanced primary forces acting in the plane of the wheel
Which one of the following is lightest?
A.1 Metric tonne
B.1 British ton
C.1 US short ton
D.1 US long ton
In locomotives the unbalanced part of the primary disturbing force due to reciprocating masses, cause
A.Hammer blow
B.Lifting of locomotive
C.Periodical vibrations
D.Variation of tractive effect
E.Oscillation in vertical planes
