1. How many turning pairs are there in a double slider crank chain?
a) 1
b) 2
c) 3
d) 4
Explanation: Double slider crank chain is a kinematic chain which consists of two turning pairs, as a result it is called double slider crank chain
2. A double slider crank chain has one pair of each sliding and turning pairs.
a) True
b) False
Explanation: In a double slider crank chain, there are two turning pairs and two sliding pairs. In a single slider crank chain there is one sliding pair and three turning pairs.
3. How many sliding pairs are there in a double slider crank chain?
a) 1
b) 2
c) 3
d) 4
Explanation: Double slider crank chain is a kinematic chain which consists of two sliding pairs, as a result it is called double slider crank chain
4. In which of the following mechanisms inversion is obtained by fixing the cylinder?
a) Pendulum pump
b) Gnome engine
c) Double slider crank chain
d) Oscillating cylinder
Explanation: Pendulum pump also known as the bull engine is an inversion of single slider crank chain, here inversion is obtained by fixing the cylinder.
5. Which of the following is not an inversion of double slider crank chain?
a) Elliptical trammels
b) Scotch yoke mechanism
c) Oldham’s coupling
d) Gnome engine
Explanation: Gnome engine is an example of inversion of single slider crank chain, whereas Elliptical trammels, Scotch yoke mechanism and Oldham’s coupling are inversions of double slider crank chain.
6. There are two points P and Q on a planar rigid body. The relative velocity between the two points
a) should always be along PQ
b) can be oriented along any direction
c) should always be perpendicular to PQ
d) should be along QP when the body undergoes pure translation
Explanation: Velocity of any point on a link with respect to another point (relative velocity) on the same link is always perpendicular to the line joining these points on the configuration (or space) diagram.
vQP = Relative velocity between P & Q
= vP − vQ always perpendicular to PQ.
7. For a four-bar linkage in toggle position, the value of mechanical advantage is
a) 0.0
b) 0.5
c) 1.0
d) ∞
Explanation: When the mechanism is toggle,then β = 00 and 1800.
So M.A = ∞.
8. The number of inversion for a slider crank mechanism is
a) 6
b) 5
c) 4
d) 3
Explanation: For a 4 bar slider crank mechanism, there are the number of links or inversions are 4. These different inversions are obtained by fixing different links once at a time for one inversion. Hence, the number of inversions for a slider crank mechanism is 4.
9. Match the item in columns I and II
Column I Column II
P. Addendum 1. Cam
Q. Instantaneous centre of velocity 2. Beam
R. Section modulus 3. Linkage
S. Prime circle 4. Gear
a) P-4, Q-2, R-3, S-1
b) P-4, Q-3, R-2, S-1
c) P-3, Q-2, R-1, S-4
d) P-3, Q-4, R-1, S-2
Explanation: Column I Column II
P. Addendum 4. Gear
Q. Instantaneous centre of velocity 3. Linkage
R. Section modulus 2. Beam
S. Prime circle 1. Cam
So correct pairs are, P-4, Q-3, R-2, S-1.
10. In a four-bar linkage, S denotes the shortest link length, L is the longest link length, P and Q are the lengths of other two links. At least one of the three moving links will rotate by 3600 if
a) S + L < P + Q
b) S + L > P + Q
c) S + P < L + Q
d) S + P > L + Q
Explanation: Here P,Q,R, & S are the lengths of the links.
According to Grashof’s law : “For a four bar mechanism, the sum of the shortest and longest link lengths should not be greater than the sum of remaining two link lengths, if there is to be continuous relative motion between the two links
S + L < P + Q.