Machine Kinematics Multiple Choice Questions on “Kinematic Link or Element”.
1. In a reciprocating steam engine, which of the following forms a kinematic link?
a) cylinder and piston
b) piston and connecting rod
c) crankshaft and flywheel
d) flywheel and engine frame
Answer: c
Clarification: Each part of a machine which moves relative to some other part, is known as a kinematic link. The piston and cylinder in a steam engine, form a pair and the motion of the piston is limited to a definite direction relative to the cylinder irrespective of the direction of motion of the crank.
2. A link or element need not to be a rigid body, but it must be a resistant body.
a) True
b) False
Answer: a
Clarification: A body is said to be a resistant body if it is capable of transmitting the required forces with negligible deformation. A link or element need not to be a rigid body, but it must be a resistant body.
3. A railway bridge is an example of a machine.
a) True
b) False
Answer: b
Clarification: When a mechanism is required to transmit power or to do some particular type of work, then it becomes a machine. A railway bridge remains static and there is no motion in it. Hence, it is not a machine.
4. The motion between a pair when limited to a definite direction, irrespective of the direction of force applied, is known as
a) completely constrained motion
b) incompletely constrained motion
c) successfully constrained motion
d) none of the mentioned
Answer: a
Clarification: When the motion between a pair is limited to a definite direction irrespective of the direction of force applied, then the motion is said to be a completely constrained motion.
5. The motion between a pair which takes place in ____________ is known as incompletely constrained motion.
a) one direction only
b) more than one direction
c) opposite direction
d) none of the mentioned
Answer: b
Clarification: When the motion between a pair can take place in more than one direction, then the motion is called an incompletely constrained motion.
6. When the connection between the elements forming a pair is such that the constrained motion is not completed by itself, but by some other means, the motion is said to be a completely constrained motion.
a) True
b) False
Answer: b
Clarification: When the motion between a pair is limited to a definite direction irrespective of the direction of force applied, then the motion is said to be a completely constrained motion.
When the connection between the elements forming a pair is such that the constrained motion is not completed by itself, but by some other means, the motion is said to be a successfully constrained motion.
7. The example of completely constrained motion is
a) motion of a piston in the cylinder of a steam engine
b) motion of a square bar in a square hole
c) motion of a shaft with collars at each end in a circular hole
d) all of the mentioned
Answer: d
Clarification: When the motion between a pair is limited to a definite direction irrespective of the direction of force applied, then the motion is said to be a completely constrained motion. In all the above mechanism, motion is limited, so they all are examples of completely constrained motion.
8. The motion of a shaft in a circular hole is an example of
a) completely constrained motion
b) incompletely constrained motion
c) successfully constrained motion
d) none of the mentioned
Answer: b
Clarification: When the motion between a pair can take place in more than one direction, then the motion is called an incompletely constrained motion. A circular bar or shaft in a circular hole, is an example of an incompletely constrained motion as it may either rotate or slide in a hole.
9. The example of successfully constrained motion is a
a) motion of an I.C. engine valve
b) motion of the shaft between a foot-step bearing
c) piston reciprocating inside an engine cylinder
d) all of the mentioned
Answer: d
Clarification: When the connection between the elements forming a pair is such that the constrained motion is not completed by itself, but by some other means, the motion is said to be a successfully constrained motion. so, the above examples have successfully constrained motion.
10. Which of the following statement is wrong?
a) A round bar in a round hole form a turning pair
b) A square bar in a square hole form a sliding pair
c) A vertical shaft in a foot step bearing forms a successful constraint
d) All of the mentioned
Answer: c
Clarification: None