MECHANISM AND MACHINE

Q.1 Which of the following is the example of lower pairs?

A. Automobile steering gear

B. Shaft revolving in a bearing

C. Straight line motion Mechanisms

D. All of the above

Ans-: D

Q.2 What is the purpose of link?

A. Transmit motion

B. Act as a support

C. Guide other links

D. All of the above

Ans-: D

Q.3 A simple Mechanism has ____ links.

A. 1

B. 4

C. 2

D. 3

Ans-: B

Q.4 Pulley in a belt drive acts as __.

A. Rolling pair

B. Surface pair

C. Sliding pair

D. All off the above

Ans-: A

Q.5 Which of the following is a lower pair?

A. Belt drive

B. Ball and socket

C. Piston and cylinder

D. B+C

Ans-: D

Q.6 A universal joint is an example of___.

A. Rolling pair

B. Higher pair

C. Lower pair

D. Turning pair

Ans-: C

Q.7 Which of the following is a closed pair ?

A. Lower pair

B. Higher pair

C. Turning pair

D. Sliding pair

Ans-: A

Q.8 A joint of two elements permitting relative motion is known as

A. Kinematic pair

B. Lower pair

C. Higher pair

D. Sliding pair

Ans-: A

Q.9 A pair having a point contact or line contact is called ____.

A. Closed pair

B. Higher pair

C. Turning pair

D. None of the above

Ans-: B

Q.10 Unconstrained rigid link in a plane has ____ of freedom.

A. Three degree

B. Two degree

C. Zero degree

D. None of the above

Ans-: A

LINK AND PAIRS

LINK -: Every part of a machine having motion re-lative to some other part is called link. In other words a link is defined as a rigid body having two or more pairing elements which connect it to the other bodies for the purpose of transmitting force or motion.                                                                      In every machine, at least one link either occupies a fixed position . And also carries the machine as a whole along with it during motion. A example of link is bicycle chain silver necklace etc.

PAIRS -:                                                                                   In a machine when two links or elements are contact ecah other ,they form a pair. If the relative motion between them is completely or successfully constrained in a definite direction, then the pair is known as Kinematic pair.

LOWER PAIR-:                                                                     The Lower pairs are those in which two elements have surface contact and relative motion takes place between them, e.g. nut and the screw, the universal joint used to connect two propeller shafts. A lower pair is an ideal joint that constrains contact between a surface in moving body to a corresponding surface in the fixed body.

HIGHER PAIR-:                                                                     The higher pairs have the line or point contact and pair is forced-closed in order to provide completely constrained motion. Two ele-ments held together mechanically from a closed pair and those not held together mechanically from unclosed pair.

KINEMATIC CHAIN

KINEMATIC CHAIN -: A kinematic chain is one in which the number of links are so connected that the relative motion of any point on a link with re-spect to any other point on the other link follows a law.

For a kinematic chain the relationship between number of links L and number of joints J is -

L = 2/3 ( J+2 )

In the above equation, each higher pair is taken equivalent to two lower pairs and an additional link.

MECHANISM

MECHANISM-:                                                                        A mechanism is a device which is designed to transform input forces and movement into a set of output forces and movement.It is formed when one link for kinematic chain is fixed, and the arra-ngement is used for transmitting or transforming motion. 

Mechanisms generally consist of moving compo-nents such as gears and gear trains, belt and the chain drives, cam and follower mechanisms, and linkages.

            Mechanism also consist of friction devices such as brakes and clutches, structural compone-nts such as the frame, bearing lubricants fastene-rs , springs and seals and also consist specialized machine elements such as pins, keys made splines. Each mechanism is termed as inversion of the original kinematic chain. The mechanism obtained in this way may be very different in the appearance and in the purposes for which they are used.

STRENGTH OF MATERIAL MCQ-11

Q.1 Principal plane is one which shear stress is__.

A. One

B. Zero

C. Two

D. Three

Ans-: B

Q.2 The normal stress on the shear plane is ____.

A. Zero

B. Maximum

C. Minimum

D. None of the above

Ans-: A

Q.3 Where bending moment is maximum,what is the value of shear force?

A. One 

B. Two

C. Zero

D. Four

Ans-: C

Q.4 The volumetric strain of cylindrical bar is equal to sum of longitudinal strain and twice of __.

A. Strain

B. Stress

C. Shear stress

D. Diameteral strain

Ans-: D

Q.5 The bending moment at hinge is ___.

A. One

B. Two

C. Three

D. Zero

Ans-: D

Q.6 The rate of change of shear force is equal to

A. Load

B. Stress

C. Shear strain

D. None of the above

Ans-: A

Q.7 The ability of a material to absorb energy in the elastic region when strained is called?

A. Elasticity

B. Malleability

C. Resilience

D. Ductility

Ans-: C

Q.8 The radius of mohr's circle represent tha value of _____ shear stress.

A. Minimum

B. Maximum

C. Constant

D. None of the above

Ans-: B

Q.9 A vertical structural member subjected to the compression is known as___.

A. Strut

B. Beam

C. Cantilever beam

D. Column

Ans-: D

Q.10 A inclined member subjected to compression is Known as____.

A. Column

B. Beam

C. Strut

D. None of the above

Ans-: C

STRENGTH OF MATERIAL MCQ-10

Q.1 How much is infinite life for steel components?

A. One thousand cycles

B. One million cycles

C. One billion cycles

D. Zero cycles

Ans-: B

Q.2 Whta is the bending moment at hinge of beam ?

A. One 

B. Two

C. Zero

D. 1/2

Ans-: C

Q.3 The function of an idler pulley is to _____ tension in the belt.

A. Increase

B. Decrease

C. Constant

D. None of the above

Ans-: A

Q.4 What will be the the bending moment at that section ? Where the shear force is zero along a section.

A. Minimum

B. Zero

C. Maximum

D. Two times

Ans-: C

Q.5 A beam which is supported on more than two supports known as___.

A. Fixed beam

B. Two supports beam

C. Cantilever beam

D. Continuous beam

Ans-: D

Q.6 A ______ is one in which the ends are rigidly fixed in a horizontal position.

A. Fixed beam

B. Continuous beam

C. Cantilever beam

D. None of the above

Ans-: A

Q.7 The line to which longitudinal axis of a beam bends under a given load is called?

A. Bending line

B. Plastic line

C. Elastic line

D. Fatigue line

Ans-: C

Q.8 In the designing of clutch what criteria is adopted from safety consideration?

A. Uniform design

B. Low coast material

C. Uniform wear

D. Uniform tear

Ans-: C

Q.9 What is the ratio of maximum shear stress to average shear stress in a beam of rectangular section?

A. 1:2

B. 1:5

C. 2:3

D. 1:4

Ans-: B

Q.10 Solderberg equation is based on the __.

A. Tensile strength of material

B. Compressive stress of material

C. Ultimate strength of material

D. Yield Strength of material

Ans-: D

STRENGTH OF MATERIAL MCQ-09

Q.1 Stress in a beam and the second modulus are _____.

A. Inversely proportional

B. Directly proportional

C. Equal

D. None of the above

Ans-: A

Q.2 According to Hooke's law, stress and strain are _____.

A. Equal

B. Inversely proportional

C. Directly proportional

D. None of the above

Ans-: C

Q.3 Principal plane carry ____ shear stress.

A. Maximum

B. No 

C. Minimum

D. None of the above

Ans-: B

Q.4  On the mutually perpendicular planes shear stress are ___.

A. Zero

B. Maximum

C. One

D. Equal

Ans-: D

Q.5 Stress in a beam and moment are 

A. Directly proportional

B. Inversely proportional

C. Equal

D. Zero

Ans-: A

Q.6 The steel bars in a concrete beam are embedded ___.

A. At top section

B. Near the top section

C. Near bottom section

D. Any where

Ans-: C

Q.7 The ratio of coil diameter to wire diameter of spring is known as ____.

A. Coil index

B. Spring index

C. Spring capacity

D. None of the above

Ans-: B

Q.8 Which types of beams occur the points of contraflexure?

A. Fixed beam

B. Overhanging beam

C. Cantilever beam

D. A+B

Ans-: D

Q.9 What is the bending moment at hinge?

A. Zero

B. One 

C. 1/4

D.1/2

Ans-: A

Q.10 Stiffness of a beam is ____ to the deflection.

A. Directly proportional

B. Equal

C. Zero

D. Inversely proportional

Ans-: D