If opposite links in a four-bar mechanism are equal in length, what geometric configuration do they always form_________________?
Show answer Hide answer
Answer: C. parallelogram
Explanation
When opposite links in a four-bar mechanism are equal, they always form a parallelogram. Equal opposite side lengths guarantee that opposite links remain parallel throughout complete rotation cycles. This specific geometric property defines parallelogram linkages used widely in mechanical engineering applications. A four-bar mechanism consists of four rigid links connected in a closed kinematic chain. Grashof's law classifies these linkages based on the relative lengths of their constituent links. Parallelogram linkages maintain constant angular orientation between input and output links during motion.
Drafting machines use parallelogram mechanisms to keep rulers oriented parallel across drawing boards. Automobile suspension systems often employ similar linkages to control wheel motion effectively. Cranes and material handling equipment utilize these geometric configurations for lifting heavy loads. Option A describes a three-sided polygon which cannot represent a standard four-bar linkage. Option B is incorrect because rectangles require interior right angles that linkages do not guarantee. Option D and E describe polygons with different numbers of sides or non-parallel configurations.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. What components comprise a Davis steering gear__________________?
Show answer Hide answer
Answer: A. sliding pairs
Davis steering mechanisms utilize sliding blocks moving inside guide bars to achieve proper vehicle turning geometry. The inclusion of these translating components distinguishes the Davis system from alternative automoti...
Q2. For a given lift and angle of ascent, what is the effect of using a smaller cam base circle_______________?
Show answer Hide answer
Answer: B. a large value of pressure angle
Using a smaller cam base circle for a given lift and ascent angle increases the steepness of the cam profile. This steeper slope causes the follower to push outward at a sharper angle, resulting in a larger pressure angl...
Q3. What kinematic pair is formed when two moving elements maintain surface contact during operation_________________?
Show answer Hide answer
Answer: D. lower pair
Surface contact between moving elements is the defining characteristic of lower kinematic pairs. A sliding or turning action distributes loads across a wide area instead of concentrated points. This broad contact area en...
Q4. For a mechanism containing L links, how many kinematic inversions are possible_______________?
Show answer Hide answer
Answer: C. L
A kinematic inversion is created by fixing a different link in a mechanism relative to a reference frame. Since a mechanism containing L links has exactly L distinct links available, it yields L unique inversions. Changi...
Q5. In a four-bar linkage with a 50 mm crank and 70 mm follower, what is the theoretical maximum coupler length for continuous follower oscillation________________________?
Show answer Hide answer
Answer: B. slightly less than 95 mm
Grashof law and triangle inequalities dictate the allowable length limits for continuous follower oscillation in linkages. For the given 50 mm crank and 70 mm follower, the maximum coupler length must be slightly less th...
Q6. For simple harmonic motion of a follower, what does a cosine curve represent___________________?
Show answer Hide answer
Answer: C. acceleration diagram
Differentiation of simple harmonic displacement yields velocity and subsequent differentiation yields acceleration curves. The second derivative of a sine displacement function results directly in a cosine acceleration p...