Question 2
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is a turning pair ?
Explanation: When the two elements of a pair are connected in such a way that one can only turn or revolve about a fixed axis of another link, the pair is known as turning pair. A shaft with collars at both ends fitted into a circular hole, the crankshaft in a journal bearing in an engine, lathe spindle supported in head stock, cycle wheels turning over their axles etc. are the examples of a turning pair.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
The motion of a piston in the cylinder of a steam engine is an example of
Explanation: The piston and cylinder in a steam engine form a pair and the motion of the piston is limited to a definite direction (i.e. it will only reciprocate) relative to the cylinder irrespective of the direction of motion of the crank.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
The motion transmitted between the teeth of gears in mesh is
Explanation: When the two elements of a pair have a line or point contact when relative motion takes place and the motion between the two elements is partly turning and partly sliding, and in mesh the gears have a point contact.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
The relation between the number of links (l) and the number of binary joints ( j) for a kinematic chain having constrained motion is given by j = 3/2 I -2 If the left hand side of this equation is greater than right hand side, then the chain is
Explanation: If the left hand side is greater than the right hand side, therefore it is not a kinematic chain and hence no relative motion is possible. Such type of chain is called locked chain and forms a rigid frame or structure which is used in bridges and trusses.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
A kinematic chain is known as a mechanism when
Explanation: When one of the links of a kinematic chain is fixed, the chain is known as mechanism. It may be used for transmitting or transforming motion e.g. engine indicators, typewriter etc.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
In a reciprocating steam engine, which of the following forms a kinematic link ?
Explanation: in a reciprocating steam engine, piston, piston rod and crosshead constitute one link ; connecting rod with big and small end bearings constitute a second link ; crank, crank shaft and flywheel a third link and the cylinder, engine frame and main bearings a fourth link.