# Theory of Machines Questions and Answers – Straight Line Mechanisms

This set of Theory of Machines Multiple Choice Questions & Answers (MCQs) focuses on “Straight Line Mechanisms”.

1. Identify the given straight line mechanism.

a) Hart’s mechanism
b) Peaucellier mechanism
c) Tchebicheff’s mechanism
d) Watt’s mechanism

Explanation: The given straight line mechanism is called Peaucellier mechanism. Peaucellier mechanism is used for converting an input circular motion to an exact straight line motion. This mechanism has 8 members and 6 joints. Two links having equal length are connected at opposite ends to a rhombus.

2. Identify the given straight line mechanism.

a) Hart’s mechanism
b) Tchebicheff’s mechanism
c) Grasshopper mechanism
d) Watt’s mechanism

Explanation: The given straight line mechanism is called Watt’s mechanism. It consists of three links. Two of them are of equal length whereas one is shorter. Due to the rotation motion of the longer links, the centre of the shorter link traces an approximate straight line. Hence, this mechanism is classified under approximate straight line mechanisms.

3. Identify the given straight line mechanism.

a) Hart’s mechanism
b) Tchebicheff’s mechanism
c) Scott Russell’s mechanism
d) Robert’s mechanism

Explanation: The given straight line mechanism is called Scott Russell’s mechanism. It consists of one short and a long link. The length of the shorter link is approximately equal to the half of the longer link. The bottom part of the longer link traces a straight line.

4. Which of these is an approximate straight line motion mechanism?
a) Scott Russell’s mechanism
b) Hart’s mechanism
c) Peaucellier mechanism
d) Watt’s mechanism

Explanation: Watt’s consists of three links. Two of them are of equal length whereas one is shorter. Due to the rotation motion of the longer links, the centre of the shorter link traces an approximate straight line. Out of the following mechanism, Watt’s mechanism is an approximate straight line mechanism whereas the rest are exact straight line mechanisms.

5. Identify the given straight line mechanism.

a) Hart’s mechanism
b) Modified Scott Russel mechanism
c) Peaucellier mechanism
d) Tchebicheff’s mechanism

Explanation: The given straight line mechanism is called Modified Scott Russel mechanism. It is similar to Scott Russell’s mechanism. The working of it is similar to Scott Russel mechanism.
Sanfoundry Certification Contest of the Month is Live. 100+ Subjects. Participate Now!

6. Identify the given straight line mechanism.

a) Grasshopper mechanism
b) Hart’s mechanism
c) Peaucellier mechanism
d) Tchebicheff’s mechanism

Explanation: The given straight line mechanism is called Grasshopper mechanism. It is an improvement over modified Scott Russel mechanism. The point P does not trace an exact straight line. It is an approximate straight line motion.

7. Which of the given mechanisms is an exact straight line motion mechanism?
a) Grasshopper mechanism
b) Robert’s mechanism
c) Peaucellier mechanism
d) Tchebicheff’s mechanism

Explanation: Peaucellier mechanism is used for converting an input circular motion to an exact straight line motion. This mechanism has 8 members and 6 joints. Two links having equal length are connected at opposite ends to a rhombus. Peaucellier mechanism is an exact straight line motion mechanism whereas the rest of them are approximate straight line motion mechanism.

8. Identify the given straight line mechanism.

a) Tchebicheff’s mechanism
b) Hart’s mechanism
c) Robert’s mechanism
d) Peaucellier mechanism

Explanation: The given straight line mechanism is called Robert’s mechanism. This mechanism has the form of a trapezium. The point P traces an approximate straight line. Thus, Robert’s mechanism is classified under approximate straight line mechanism.

9. Identify the given straight line mechanism.

a) Chebychev mechanism
b) Tchebicheff’s mechanism
c) Robert’s mechanism
d) Peaucellier mechanism

Explanation: The given straight line mechanism is called Chebychev mechanism. This mechanism is used for converting rotary motion to an approximate straight line motion. The point P traces an approximate straight line mechanism.

10. Hart’s mechanism requires only eight links whereas the Peaucellier mechanism requires six links. True or false?
a) True
b) False

Explanation: Hart’s mechanism requires only six links whereas the Peaucellier mechanism requires eight links and contains 6 joints. Thus, the statement is false.

11. __________ mechanism is a crossed four bar chain mechanism in early steam engines to guide the piston rod in a cylinder to have an approximate straight line motion.
a) Peaucellier’s
b) Chebychev’s
c) Grasshopper
d) Watt’s

Explanation: Watt’s mechanism is a four bar chain mechanism and was used by Watt in steam engines so as to guide the piston rod into a cylinder to have a straight line motion. Due to the rotation motion of the longer links, the centre of the shorter link traces an approximate straight line.

Sanfoundry Global Education & Learning Series – Theory of Machines.

To practice all areas of Theory of Machines, here is complete set of 1000+ Multiple Choice Questions and Answers.