Engineering Questions with Answers - Multiple Choice Questions

# Machine Kinematics – Linear Velocity – 1

1 - Question

The relative velocity of B with respect to A in a rigid link AB is
a) parallel to AB
b) perpendicular to AB
c) along AB
d) at 450
Explanation: The relative velocity of any two points on a rigid link is always normal to the line joining the two points.

2 - Question

The magnitude of linear velocity of a point B on a link AB relative to point A is
a) ω x AB
b) ω(AB)2
c) ω2AB
d) (ω x AB)2
Explanation: None

3 - Question

The direction of linear velocity of any point on a link with respect to another point on the same link is
a) parallel to the link joining the points
b) perpendicular to the link joining the points
c) at 450 to the link joining the points
d) none of the mentioned
Explanation: The relative velocity of any two points on a rigid link is always normal to the line joining the two points.

4 - Question

The two links OA and OB are connected by a pin joint at O. If the link OA turns with angular velocity ω1 rad/s in the clockwise direction and the link OB turns with angular velocity ω2 rad/s in the anti-clockwise direction, then the rubbing velocity at the pin joint O is
a) ω1.ω2.r
b) (ω1-ω2)r
c) (ω1+ω2)r
d) (ω1-ω2)2r
Explanation: Consider two links OA and OB connected by a pin joint at O Let ω1 = Angular velocity of the link OA or the angular velocity of the point A with respect to O. ω2 = Angular velocity of the link OB or the angular velocity of the point B with respect to O, and r = Radius of the pin. According to the definition, Rubbing velocity at the pin joint O = (ω1 – ω2) r, if the links move in the same direction = (ω1 + ω2) r, if the links move in the opposite direction

5 - Question

In the above question, if both the links OA and OB turns in clockwise direction, then the rubbing velocity at the pin joint O is
a) ω1.ω2.r
b) (ω1-ω2)r
c) (ω1+ω2)r
d) (ω1-ω2)2r
Explanation: Consider two links OA and OB connected by a pin joint at O Let ω1 = Angular velocity of the link OA or the angular velocity of the point A with respect to O. ω2 = Angular velocity of the link OB or the angular velocity of the point B with respect to O, and r = Radius of the pin. According to the definition, Rubbing velocity at the pin joint O = (ω1 – ω2) r, if the links move in the same direction = (ω1 + ω2) r, if the links move in the opposite direction

6 - Question

ABCD is a four bar mechanism in which AB = 310mm and CD = 450mm. AB and CD are both perpendicular to the fixed link AD. If the velocity of B at this condition is v. Then the velocity of C is
a) v
v) 2/3 v
c) 3/2 v
d) 9/4 v
Explanation: Velocity at C = CD/AB x velocity at B = 450/310 x v = 3/2 v

7 - Question

A thin circular disc is rolling with a uniform linear speed, along a straight path on a plane surface. Which of the following statement is correct in this regard?
a) All points of the disc have the same velocity.
b) The centre of the disc has zero acceleration.
c) The centre of the disc has centrifugal acceleration.
d) The point on the disc making contact with the plane surface has zero acceleration.
Explanation: None

8 - Question

The component of the accelertion, parallel to the velocity of the particle, at the given instant is called
b) tangential component
c) coriolis component
d) none of the mentioned
Explanation: The centripetal or radial component, is perpendicular to the velocity of the particle at the given instant. The tangential component, is parallel to the velocity of the particle at the given instant.

9 - Question

The component of the accelertion, perpendicular to the velocity of the particle, at the given instant is called a) radial component
b) tangential component
c) coriolis component
d) none of the mentioned
Explanation: The centripetal or radial component, is perpendicular to the velocity of the particle at the given instant. The tangential component, is parallel to the velocity of the particle at the given instant.

10 - Question

A point B on a rigid link AB moves with respect to A with angular velocity ωrad/s. The total acceleration of B with respect to A will be equal to
a) vector sum of radial component and coriolis component
b) vector sum of tangential component and coriolis component
c) vector sum of radial component and tangential component
d) vector difference of radial component and tangential component