Mechanism Kinematic Analysis Practice Quiz (10 questions)

1. Which statements characterize a mechanism?

A. A mechanism may be assembled from rigid bodies, flexible bodies, or both types.

B. A mechanism combines rigid or flexible bodies connected to perform work through constrained relative motion.

C. A mechanism performs work, distinguishing it from a structure with stationary parts.

D. A mechanism has definite constrained relative motions between its connected parts.

E. A mechanism combines connected bodies whose relative motion is unconstrained while they perform work.

Answer: (A), (B), (C), (D)

Explanation

A mechanism consists of connected rigid and/or flexible bodies that do work through definite constrained relative motions. Its components may be rigid, flexible, or both; unconstrained motion is not the defining relation. A structure does not do work and has no relative motion between its parts.

2. Kinematics concerns the geometry of motion. Which quantities or characteristics fall within its scope?

A. Kinematics can describe motion without making its analysis depend on applied forces.

B. Kinematics includes speed, velocity, and acceleration as characteristics of motion.

C. Kinematics explains motion by identifying the forces responsible for producing it.

D. Kinematics examines motion geometry without considering the forces that cause the motion.

E. Kinematics includes the study of position, displacement, and rotation during motion.

Answer: (A), (B), (D), (E)

Explanation

Kinematics studies motion geometry independently of the forces causing motion, and its scope includes position, displacement, rotation, speed, velocity, and acceleration. An explanation centered on the forces producing motion is not kinematics as defined here.

3. External system analysis focuses on which part of a system?

A. External analysis studies the components located inside the object-of-interest boundaries.

B. External analysis considers factors situated outside the object selected for study.

C. External analysis examines the environment beyond the defined system boundary.

D. External analysis defines the internal construction of the object under investigation.

E. External analysis identifies and studies the environment outside the object-of-interest boundaries.

Answer: (B), (C), (E)

Explanation

External analysis identifies and studies the environment outside the boundaries of the object of interest. The internal components and construction lie within those boundaries, so they are not the focus described by this definition.

4. Which items are identified in an external analysis?

A. External analysis identifies the system’s global function and surrounding environment.

B. External analysis establishes the boundaries used to define the system under study.

C. External analysis identifies the operating phases considered in the system’s study.

D. External analysis identifies input and output parameters but excludes operating phases.

E. External analysis identifies the input and output parameters associated with the system.

Answer: (A), (B), (C), (E)

Explanation

External analysis identifies the global function, environment, study boundaries, input/output parameters, and operating phases. Operating phases are part of the analysis, so an account that excludes them is incomplete and incorrect.

5. What is a degree of freedom of a body?

A. The number of directions in which the body can translate without rotating

B. The number of independent parameters needed to determine its position uniquely at an instant

C. The number of points on the body that can serve as centers of rotation

D. The number of forces that can act on the body without changing its motion

Answer: (B)

Explanation

A degree of freedom counts the independent parameters required to specify a body's position uniquely at a given instant. The number of forces acting on a body is not what defines its degrees of freedom.

6. How many joints does a simple link contain?

A. Six joints

B. One joint

C. More than two joints

D. Two joints

Answer: (D)

Explanation

A simple link contains two joints, while a complex link has more than two. The “more than two” description applies to a complex link, not a simple one.

7. What is the purpose of recording non-movement relationships between parts in a kinematic analysis graph?

A. To represent each group’s possible movement with a joint symbol

B. To identify the forces transmitted across moving joints

C. To show which parts belong to the same group without relative motion

D. To establish the mechanism’s operating phase and input parameters

Answer: (C)

Explanation

Recording non-movement relationships identifies parts that move together as a group, helping organize the mechanism for later analysis of relative motions. Joint symbols instead represent connections between groups that can move relative to one another.

8. At what point in preparing a kinematic diagram should the diagram be drawn?

A. After choosing the input and output, before determining relative motions between groups

B. Before identifying groups, to establish the mechanism’s overall shape and joint locations

C. After identifying the link graph, while preserving the mechanism’s form, positions, and orientations

D. After assigning colours, so the graph can be converted into a diagram of the mechanism

Answer: (C)

Explanation

The kinematic diagram follows identification of the link graph and should preserve the mechanism’s form, positions, and orientations. Determining relative motions and joints is part of building the analysis before the diagram is drawn.

9. How do kinematics and kinetics differ in their treatment of motion?

A. Kinematics studies work-producing assemblies, while kinetics studies bodies without relative motion.

B. Kinematics combines force and motion, while kinetics studies constrained relative positions.

C. Kinematics describes motion geometrically, while kinetics relates forces to resulting motion.

D. Kinematics relates forces to motion, while kinetics describes motion geometrically.

Answer: (C)

Explanation

Kinematics examines motion without considering the forces that cause it, whereas kinetics connects forces acting on bodies with their resulting motion. The alternative that assigns force-motion relationships to kinematics reverses the distinction.

10. In the door system, what is the consequence of adjusting the screw height during the maintenance phase?

A. It converts the screw’s translation into scroll-wheel rotation during door displacement.

B. It changes the study boundary and determines which environment surrounds the door.

C. It changes the door’s global function and removes the need for hydraulic cylinders.

D. It changes when the contactor is triggered and alters the resulting kinematics.

Answer: (D)

Explanation

Changing the screw-height setting changes the trigger moment, which affects the resulting kinematics. Altering the study boundary describes a different part of external system analysis, not the effect of the adjustment.