# Theory of Machines Questions and Answers – Coupler Curves

This set of Theory of Machines Multiple Choice Questions & Answers (MCQs) focuses on “Coupler Curves”.

1. What is a coupler curve?
a) Locus of a point on the plane parallel to coupler
b) Locus of a point on the coupler link
c) Locus of a point on the plane perpendicular to coupler
d) Locus of a point on the follower link

Explanation: The coupler of a plane four-bar linkage may be imagined as an infinite plane extending in all directions but pin-connected to the input and output links. Thus, during motion of the linkage, any point attached to the plane of the coupler generates some path with respect to the fixed link which is called coupler curve.

2. How many minimum possible circles are traced by links in a four-bar mechanism?
a) 1
b) 2
c) 3
d) 4

Explanation: The driver and follower link are connected the fixed ground. Also, the lengths of the links are assumed to be constant. Hence, both driver and follower will trace circles of diameter equal to link lengths and center equal to pin-connection of links and coupler.

3. It is often not necessary to use a mechanism with a large number of links to obtain a complex motion.
a) False
b) True

Explanation: Generally, the algebraic equation of a coupler curve is of sixth order. Thus, it is possible to find coupler curves with wide variety of shapes and many interesting features.

4. What do you mean by cognate linkages?
a) The same curve can always be generated by three different linkages
b) The same curve can always be generated by two different linkages
c) The same curve can always be generated by four different linkages
d) The same curve can always be generated by relative position of coupler and driver linkage

Explanation: Coupler curve is drawn by considering the locus of a single point on connecting link. Hence, in certain cases, the same curve can be drawn using three different linkages, termed as cognate linkages.

Sanfoundry Global Education & Learning Series – Theory of Machines.

Note: Join free Sanfoundry classes at Telegram or Youtube

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

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]