Velocity in Mechanisms topics include: Point link velocity, instantaneous centre properties, velocity in mechanisms, relative velocity and slider crank mechanism. Velocity analysis is the study of the linear velocities of points on different links of a mechanism and the angular velocities of the links. It is a prerequisite for acceleration analysis, which leads to force analysis of the links.  Here are some details about velocity in mechanisms: The magnitude of velocities of points on a rigid link is inversely proportional to the distances from the points to the instantaneous center. The... Show more

Velocity in Mechanisms topics include: Point link velocity, instantaneous centre properties, velocity in mechanisms, relative velocity and slider crank mechanism.

Velocity analysis is the study of the linear velocities of points on different links of a mechanism and the angular velocities of the links. It is a prerequisite for acceleration analysis, which leads to force analysis of the links. 

Here are some details about velocity in mechanisms:
The magnitude of velocities of points on a rigid link is inversely proportional to the distances from the points to the instantaneous center.
The velocity of point B with respect to A (VBA) is perpendicular to the link AB.
The radial component of acceleration acts perpendicular to the velocity VBA.
Velocity is a vector, which means it has direction and magnitude.
Acceleration is a vector quantity that is defined as the rate at which an object changes its velocity. 

Velocity can be determined by different methods, including the instantaneous center method. To determine the relative motion of the ends of a link, one of the ends is assumed to be moving relative to the other end.

Show less

Machine Kinematics Practice Test: Velocity in Mechanisms

Time left 00:00

25 Questions

1. The direction of Corioli’s component of acceleration is the direction

of relative velocity vector for the two coincident points rotated by 900 in the direction of the angular velocity of the rotation of the linkalong the centripetal accelerationalong perpendicular to angular velocityalong tangential acceleration

2. Klein’s construction is useful to determine

displacement of various partsvelocity of various partsangular acceleration of various partsacceleration of various parts

3. A machine raised a load of 360 N through a distance of 200 mm. The effort, a force of 60 N moved 1.8 m during the process. Calculate velocity ratio.

6978

4. For the same crank length and uniform angular velocity of the crank in an offset slider crank mechanism, if the connecting rod length is increased by 1.5 times, the velocity of piston will

remain unchangeddecrease by 1.5 timesincrease 1.5 timesincrease by 1.5√2 times

5. What is the direction of velocity of a point in a link relative to another point on the same link rotating in a specific direction.

Parallel to line joining both the linksParallel to the surface of the linkPerpendicular to the surface of the linkPerpendicular to line joining both the links

6. Match the items in columns I and II
Column I Column II
P. Higher Kinematic Pair 1. Grubler’s Equation
Q. Lower Kinemation Pair 2. Line contact
R. Quick Return Mechanism 3. Euler’s Equation
S. Mobility of a Linkage 4. Planar
5. Shaper
6. Surface contact

P-2, Q-6, R-4, S-3P-6, Q-2, R-4, S-1P-6, Q-2, R-5, S-3P-2, Q-6, R-5, S-1

7. In a four-bar linkage, S denotes the shortest link length, L is the longest link length, P and Q are the lengths of other two links. At least one of the three moving links will rotate by 360⁰ if

S + P > L + QS + L > P + QS + P < L + QS + L < P + Q

8. In a lifting machine, the effort required to lift loads of 200N and 300N were 50N and 60N respectively. If the velocity ratio of the machine is 20 determine efficiency to load of 300 N.

20 %15 %25 %10 %

9. In a lifting machine, the effort required to lift loads of 200N and 300N were 50N and 60N respectively. If the velocity ratio of the machine is 20 determine law of the machine.

P = 1/20W +30P = 1/10W +30P = 1/30W +30P = 1/40W +30

10. The locus of the instantaneous centre relative to the body itself is called the _________

Space centrodeMechanism centrodeBody centrodeLink centrode

11. What is the velocity of point C with respect to A in the given figure?

Parallel to line joining BCParallel to line joining ACPerpendicular to line joining ACPerpendicular to line joining BC

12. The sense of Coriol’s component is such that it

is along the sliding velocity vector by 900leads the sliding velocity vector by 900lags the sliding velocity vector by 900leads the sliding velocity vector by 1800

13. According to Kennedy’s theorem the instantaneous centres of three bodies having relative motion lie on a

straight linenone of thesepointcurved path

14. Corioli’s component acts

along sliding surfacesall of theseboth of the mentionedperpendicular to sliding surfaces

15. A machine raised a load of 360 N through a distance of 200 mm. The effort, a force of 60 N moved 1.8 m during the process. Calculate efficiency at this load.

55.55%77.77%66.66%44.44%

16. Mechanism used to produce a diagram to an enlarged or reduced sacle

grasshopper mechanismhart’s mechanismpantographpeaucellier’s mechanism

17. The driving and driven shafts connected by a Hooke’s joint will have equal speeds, if

cosϴ = sinαcotϴ = cosαsinϴ = √tanαtanϴ = √cosα

18. Tangential acceleration direction is

along the angular velocityopposite to angular velocityperpendicular to angular velocityall of these

19. Two systems shall be dynamically equivalent when

c.g. of two coincidesall of theseM.I. of two about an axis through c.g. is equalthe mass of two are same

20. There are two points P and Q on a planar rigid body. The relative velocity between the two points

can be oriented along any directionshould be along QP when the body undergoes pure translationshould always be along PQshould always be perpendicular to PQ

21. The instantaneous centers of a slider moving in a linear guide lies at

infinitynone of thesetheir point of contactpin joints

22. Corioli’s component is encountered in

quick return mechanism of shaperall of theseslider crank mechanismfour bar chain mechanism

23. Following are the specifications of a single purchase crab:
Diameter of load drum, d = 200 mm
Length of lever, l = 1.2 m
No. of teeth on pinion, T₁ = 10
No. of teeth on spur wheel, T₂ = 100
On this machine efforts of 100 N and 160 N are required to lift the loads of 3000 N and 9000 N respectively. Find the efficiency at 9000N.

56.8 %46.8 %40 %30 %

24. Which of the following is a lower pair?

Belt driveBall and socket jointCam and followerPulleys in belt drive

25. Match the item in columns I and II
Column I Column II
P. Addendum 1. Cam
Q. Instantaneous centre of velocity 2. Beam
R. Section modulus 3. Linkage
S. Prime circle 4. Gear

P-3, Q-4, R-1, S-2P-4, Q-2, R-3, S-1P-4, Q-3, R-2, S-1P-3, Q-2, R-1, S-4