Kinematics of Machinery Questions and Answers Part-19

1. 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

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

2. 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

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)

3. 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

Answer: b
Explanation: two lower pairs and one additional link

4. 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 (l – 2). If the left hand side of this equation is greater than the right hand side, then the chain is
a) locked chain
b) completely constrained chain
c) successfully constrained chain
d) incompletely constrained chain

Answer: a
Explanation: If the L.H.s. > R.H.S., then the chain is called a locked chain and forms a frame or structure which is used in bridges and trusses.

5. A chain consisting of four links and four joints is called a kinematic chain.
a) True
b) False

Answer: a
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.

6. In a kinematic chain, a quaternary joint is equivalent to
a) one binary joint
b) two binary joints
c) three binary joints
d) four binary joints

Answer: c
Explanation: When four links are joined at the same connection, the joint is called a quaternary joint. It is equivalent to three binary joints

7. In a steam engine, the link constitutes a
a) piston, piston rod and cross-head
b) connecting rod with big and small end brasses, caps and bolts
c) crank pin, crankshaft and flywheel
d) all of the mentioned

Answer: d
Explanation: all of the mentioned

8. A mechanism is a assemblage of
a) two links
b) three links
c) four or more than four links
d) all of the mentioned

Answer: c
Explanation: When one of the links of a kinematic chain is fixed, the chain is known as mechanism. A simple mechanism consists of minimum four links.

9. A mechanism consisting of four links is called a _____________ mechanism.
a) simple
b) compound
c) inversion
d) none of the mentioned

Answer: a
Explanation: A mechanism with four links is known as simple mechanism, and the mechanism with more than four links is known as compound mechanism.

10. A mechanism ______________ for transmitting or transforming motion.
a) can be used
b) can not be used
c) both of the mentioned
d) none of the mentioned

Answer: a
Explanation: A mechanism is used for transmitting or transforming motion e.g. engine indicators, typewriter etc.