Engineering Questions with Answers - Multiple Choice Questions
Machine Kinematics Questions and Answers – Kinematic Pair
1 - Question
When the two elements of a pair have _____________ when in motion, it is said to a lower pair.
a) line or point contact
b) surface contact
c) permit relative motion
d) none of the mentioned
View Answer
Answer: b
Explanation: When the two elements of a pair have surface contact when relative motion, takes place and the surface of one element slides over the surface of the other, the pair formed is known as lower pair. It will be seen that sliding pairs, turning pairs and screw pairs form lower pairs.
2 - Question
The two elements of a pair are said to form a higher pair, when they
a) have a surface contact when in motion
b) have a line or point contact when in motion
c) are kept in contact by the action of external forces, when in motion
d) permit relative motion
View Answer
Answer: b
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, then the pair is known as higher pair.
3 - Question
In a force-closed pair, the two elements of a pair are not held together mechanically.
a) True
b) False
View Answer
Answer: b
Explanation: When the two elements of pair are not connected mechanically but are kept in contact by the action of external forces, the pair is said to be a forced-closed pair.
4 - Question
The two elements of a pair are said to form a ___________ when they permit relative motion between them.
a) open pair
b) kinematic pair
c) higher pair
d) lower pair
View Answer
Answer: b
Explanation: The two links or elements of a machine, when in contact with each other, are said to form a pair. If the relative motion between them is completely or successfully constrained, the pair is known as kinematic pair.
5 - Question
In an open pair, the two elements of a pair
a) have a surface contact when in motion
b) have a line or point contact when in motion
c) are kept in contact by the action of external forces, when in motion
d) are not held mechanically
View Answer
Answer: d
Explanation: When the two elements of a pair are not held mechanically, they are called open pair.
6 - Question
The sliding pairs, turning pairs and screw pairs form lower pairs.
a) True
b) False
View Answer
Answer: a
Explanation: When the two elements of a pair have surface contact when relative motion, takes place and the surface of one element slides over the surface of the other, the pair formed is known as lower pair. It will be seen that sliding pairs, turning pairs and screw pairs form lower pairs.
7 - Question
A combination of kinematic pairs, joined in such a way that the relative motion between the links is completely constrained, is called a
a) structure
b) mechanism
c) kinematic chain
d) inversion
View Answer
Answer: c
Explanation: A kinematic chain is defined as a combination of kinematic pairs, joined in such a way that each link forms a part of two pairs and the relative motion between the links or elements is completely or successfully constrained.
8 - Question
The relation between number of pairs(p) forming a kinematic chain and the number of links(l) is
a) l = 2p – 2
b) l = 2p – 3
c) l = 2p – 4
d) l = 2p – 5
View Answer
Answer: c
Explanation: If each link is assumed to form two pairs with adjacent links, then the relation between the number of pairs(p) forming a kinematic chain and the number of links(l) may be expressed in the form of an equation : l = 2p – 4
9 - Question
The relation between number of links(l) and number of joints(j) in a kinematic chain is
a) l = 1/2 (j+2)
b) l = 2/3 (j+2)
c) l = 3/4 (j+2)
d) l = j+4
View Answer
Answer: b
Explanation: Another relation between the number of links (l) and the number of joints(j) which constitute a kinematic chain is given by the expression : l = 2/3 (j+2)
10 - Question
The relation l = 2/3(j+2) apply to kinematic chains in which lower pairs are used. This may be used to kinematic chains in which higher pairs are used, but each higher pair may be taken as equivalent to
a) one lower pair and two additional links
b) two lower pairs and one additional link
c) two lower pairs and two additional links
d) all of the mentioned
View Answer
Answer: b
Explanation: None