Engineering Questions with Answers - Multiple Choice Questions

# Machine Kinematics Questions and Answers – Velocity in Mechanisms – 1

1 - Question

In the figure given below A and D are fixed points, link AB rotates at a uniform angular velocity of 900 rev/min ccw, find the instantaneous velocity of point E in m/s.
Rab = 100mm, Bc = 450, distance of E from BC = 100mm, Cf = 75mm, CD = 275mm, AD = 250mm, perpendicular DF = 17mm, perpendicular BE = 250mm. a) 8.3
b) 8.7
c) 9
d) 7.6

Explanation: The following question can be solved graphically as well as analytically,
first we find that
Vb = ωxRab = 9.42 m/s
Vcb = 11.42
Vcd = 13.61 m/s
constructing a velocity graph, we find that
Ve = 8.3m/s.

2 - Question

Velocity of a point B in a link can be calculated by using the relation
Vb = Va – Vba.
a) True
b) False

Explanation: The velocity of a point B in a link can be calculated when the velocity of point A is known using the relation
Vb = Va + Vba.

3 - Question

In the figure given below A and D are fixed points, link AB rotates at a uniform angular velocity of 900 rev/min ccw, find instantaneous velocity of point F in m/s.
Rab = 100mm, Bc = 450, distance of E from BC = 100mm, Cf= 75mm, CD = 275mm, AD =250mm, perpendicular DF = 17mm, perpendicular BE = 250mm. a) 8.3
b) 8.7
c) 9.4
d) 7.6

Explanation: The following question can be solved graphically as well as analytically,
first we find that
Vb = ωxRab = 9.42 m/s
Vcb = 11.42
Vcd = 13.61 m/s
constructing a velocity graph, we find that
Vf = 9.4 m/s.

4 - Question

In the figure given below A and D are fixed points, link AB rotates at a uniform angular velocity of 900 rev/min ccw, find angular velocity of BC in rad/s.
Rab = 100mm, Bc = 450, distance of E from BC = 100mm, Cf= 75mm, CD = 275mm, AD =250mm, perpendicular DF = 17mm, perpendicular BE = 250mm. a) 28.3
b) 2 8.7
c) 29.4
d) 25.3

Explanation: The following question can be solved graphically as well as analytically,
first we find that
Vb = ωxRab = 9.42 m/s
Vcb = 11.42
ωcb = Vcb/Rcb

5 - Question

In the figure given below A and D are fixed points, link AB rotates at a uniform angular velocity of 900 rev/min ccw, find angular velocity of CDin rad/s.
Rab = 100mm, Bc = 450, distance of E from BC = 100mm, Cf= 75mm, CD = 275mm, AD =250mm, perpendicular DF = 17mm, perpendicular BE = 250mm. a) 48.37
b) 48.77
c) 49.47
d) 45.37

Explanation: The following question can be solved graphically as well as analytically,
first we find that
Vb = ωxRab = 9.42 m/s
Vcd = 13.61 m/s
ωcd = Vcd/Rcd

6 - Question

The locus of the instantaneous centre in space during a definite motion of the body is called the _________
a) Space centrode
b) Body centrode
d) Mechanism centrode

Explanation: The instantaneous centre is a point inside the body which may be considered fixed at any instant of time. The locus of the instantaneous centre in space during a definite motion of the body is called the space centrode.

7 - Question

The locus of the instantaneous centre relative to the body itself is called the _________
a) Space centrode
b) Body centrode
d) Mechanism centrode

Explanation: The instantaneous centre is a point inside the body which may be considered fixed at any instant of time. The locus of the instantaneous centre relative to the body itself is called the body centrode.

8 - Question

Locus of all instantaneous centres is known as centrode.
a) True
b) False

Explanation: Thus the instantaneous centre of a moving body can be defined as that centre which goes on changing from one instant to another. The locus of all such instantaneous centres is known as a centrode.

9 - Question

A line drawn through an instantaneous centre and perpendicular to the plane of motion is called __________
a) Instantaneous axis
b) Relative axis
c) Instantaneous centrode
d) Relative centrode

Explanation: A line drawn through an instantaneous centre and perpendicular to the plane of motion is called instantaneous axis. The locus of this axis is known as axode.

10 - Question

The locus of which axis is known as axode?
a) Instantaneous axis
b) Relative axis
c) Instantaneous centrode
d) Relative centrode