Engineering Questions with Answers - Multiple Choice Questions

# Machine Kinematics MCQ – Acceleration of a Point on a Link

1 - Question

Match list I with list II

List I List II
A. Law of correct steering 1. f = 3(n – 1) – 2j
B. Displacement relation of Hook’e joint 2. x = R[ (1 – cosϴ) + sin2ϴ/2n].
C. Relation between kinematic pairs and links 3. cotɸ – cotɸ = c/b
D. Displacement equation of reciprocating engine piston 4. tanϴ = tanɸ cosα
a) A-1,B-4,C-3,D-2
b) A-1,B-2,C-3,D-4
c) A-3,B-4,C-1,D-2
d) A-3,B-2,C-1,D-4

Explanation: Law of correct steering – cotɸ – cotɸ = c/b
Displacement relation of Hook’e joint – tanϴ = tanɸ cosα
Relation between kinematic pairs and links – f = 3(n – 1) – 2j
Displacement equation of reciprocating engine piston – x = R[ (1 – cosϴ) + sin2ϴ/2n].

2 - Question

Consider the following statements regarding motions in machines:
1. Tangential acceleration is a function of angular velocity and the radial acceleration is a function of angular acceleration.
2. The resultant acceleration of a point A with respect to a point B on a rotating link is perpendicular to AB.
3. The direction of the relative velocity of a point A with respect to a point B on a rotating link is perpendicular.

Which of these statements is/are correct?
a) 1 alone
b) 2 and 3
c) 1 and 2
d) 3 alone

Explanation: Only statement 1 is correct.

3 - Question

The speed of driving shaft of a Hooke’s Joint of angle 19.50 is 500 r.p.m. The maximum speed of the driven shaft is nearly
a) 168 r.p.m.
b) 444 r.p.m.
c) 471 r.p.m.
d) 531 r.p.m.

Explanation: Nmax = N/cosα = 500/cos19.50 = 531 r.p.m.

4 - Question

In a slider crank mechanism. the maximum acceleration of slider is obtained when the crank is
a) at the inner dead centre position
b) at the outer dead centre position
c) exactly midway position between the two dead centres
d) slightly in advance of the midway position between the two dead centres

Explanation: None.

5 - Question

In a shaper machine, the mechanism for tool feed is
a) Geneva mechanism
b) Whitworth mechanism
c) Ratchet and Pawl mechanism
d) Ward Leonard system

Explanation: The crank shaper, in which the tool carrier is driven forward and backward by an oscillating arm operated by a crankpin in the main driving gear, or “bull wheel,” and in which the feed is transmitted to the worktable by ratchet-and-pawl mechanism, is so commonly used as to be termed standard.

6 - Question

The instantaneous centre of rotation of a rigid thin disc rolling without slip on a plane rigid surface is located at
a) the centre of the disc
b) an infinite distance perpendicular to the plane surface
c) the point of contact
d) the point on the circumference situated vertically opposite to the contact point

Explanation: The instantaneous centre of rotation of a rigid thin disc without slip is located at the centre of the disc.

7 - Question

Match list I with list II

List I List II
A. Sliding pair 1. A road roller rolling over the ground
B. Revolute pair 2. Crank shaft in a journal bearing in an engine
C. Rolling pair 3. Ball and socket joint
D. Spherical pair 4. Piston and cylinder
5. Nut and screw
a) A-5,B-2,C-4,D-3
b) A-4,B-3,C-1,D-2
c) A-5,B-3,C-4,D-2
d) A-4,B-2,C-1,D-3

Explanation: Sliding pair – Piston and cylinder
Revolute pair – Crank shaft in a journal bearing in an engine
Rolling pair – A road roller rolling over the ground
Spherical pair – Ball and socket joint.

8 - Question

Slider crank chain is an inversion of the four bar mechanism.
a) True
b) False

Explanation: Slider crank chain often finds applications in most of the reciprocating machinery.

9 - Question

f = 3 (n – 1) – 2j. In the Gruebler’s equation for planer mechanisms given, j is the
c) Number of lower pairs
d) Length of the longest link

Explanation: None.

10 - Question

Which of the following are examples of forced closed kinematic pairs?
1. Cam and roller mechanism
2. Door closing mechanism
3. Slider crank mechanism
4. Automotive clutch operating mechanism
Select the correct answer using the codes given below:
a) 1,2 and 4
b) 1 and 3
c) 2,3 and 4
d) 1,2,3 and 4