Machine Kinematics

Simple Mechanisms

Question 1
Marks : +2 | -2
Pass Ratio : 100%
The Grubler’s criterion for determining the degrees of freedom (n) of a mechanism having plane motion is
n = (l – 1) – j
n = 2 (l – 1) – 2j
n = 3 (l – 1) – 2j
n = 4 (l – 1) – 3j
Explanation:
The Grubler’s criterion applies to mechanisms with only single degree of freedom joints where the overall movability of the mechanism is unity.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
A ball and a socket joint forms a
turning pair
rolling pair
sliding pair
spherical pair
Explanation:
When the two elements of a pair are connected in such a way that one element (with spherical shape) turns or swivels about the other fixed element, the pair formed is called a spherical pair, and ball and socket joint are such pairs.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
In a 4 – bar linkage, if the lengths of shortest, longest and the other two links are denoted by s, l, p and q, then it would result in Grashof’s linkage provided that
l + p < s + q
l + s < p + q
l + p = s + q
none of the mentioned
Explanation:
None
Question 4
Marks : +2 | -2
Pass Ratio : 100%
The cam and follower without a spring forms a
lower pair
higher pair
self closed pair
force closed pair
Explanation:
When the two elements of a pair are connected together mechanically in such a way that only required kind of relative motion occurs, it is then known as self closed pair. The lower pairs are self closed pair and the motion of cam and follower is relative to each other.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
The lead screw of a lathe with nut forms a
sliding pair
rolling pair
screw pair
turning pair
Explanation:
When the two elements of a pair are connected in such a way that one element can turn about the other by screw threads, the pair is known as screw pair. The lead screw of a lathe with nut, and bolt with a nut are examples of a screw pair.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
In a reciprocating steam engine, which of the following forms a kinematic link ?
cylinder and piston
piston rod and connecting rod
crank shaft and flywheel
flywheel and engine frame
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.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
A kinematic chain is known as a mechanism when
none of the links is fixed
one of the links is fixed
two of the links are fixed
all of the links are fixed
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 8
Marks : +2 | -2
Pass Ratio : 100%
The motion of a piston in the cylinder of a steam engine is an example of
completely constrained motion
incompletely constrained motion
successfully constrained motion
none of the mentioned
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 9
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is an inversion of double slider crank chain ?
Coupling rod of a locomotive
Pendulum pump
Elliptical trammels
Oscillating cylinder engine
Explanation:
A kinematic chain which consists of two turning pairs and two sliding pairs is known as double slider crank chain and elliptical trammels are such pairs.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
The mechanism forms a structure, when the number of degrees of freedom (n) is equal to
0
1
2
– 1
Explanation:
When n = 0, then the mechanism forms a structure and no relative motion between the links is possible.