A mechanical cam with a roller follower forms which classification of kinematic pair______________?
Show answer Hide answer
Answer: B. higher pair
Explanation
A cam mechanism with a roller follower makes point or line contact during operation. Kinematic pairs with point or line surface contact are classified as higher pairs. This contrasts with surface-to-surface contact found in standard pin joints. Theory of machines categorizes kinematic pairs based on the nature of contact between links. Lower pairs feature area contact, such as journal bearings and sliding pins. Higher pairs experience high local stresses due to concentrated point or line contact.
Cam and follower mechanisms are widely used in internal combustion engine valve trains. Engineers must design higher pairs to withstand rolling and sliding contact wear. Lubrication is essential in cam mechanisms to reduce friction at the point of contact. Lower pairs require surface contact, which does not occur in roller cam interfaces. Open pairs refer to unconstrained kinematic arrangements rather than contact types. Close pairs maintain geometric constraint but higher pair is the specific contact classification.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. What is the compressibility coefficient value for water under standard pressure and temperature conditions in kg/cm_________________?
Show answer Hide answer
Answer: E. 21,000
The bulk modulus of elasticity for water at standard conditions is approximately twenty-one thousand kg per square centimeter. This high bulk modulus value proves that water resists volumetric compression strongly under...
Q2. What are known as the three “Ts” essential for complete combustion____________________?
Show answer Hide answer
Answer: A. temperature, time, and turbulance
Sufficient temperature ensures the fuel-air mixture reaches its required ignition point instantly. Adequate time allows chemical combustion reactions to proceed completely to carbon dioxide and water. Turbulence promotes...
Q3. What is the mass density value in kgsecVm4 for water at 0°C_________________?
Show answer Hide answer
Answer: D. 101.9
Mass density in gravitational or engineering units is expressed in kilograms force-second squared per meter to the fourth power. This value is derived by dividing the standard mass density of water by the local accelerat...
Q4. What is the designated top edge over which water flows in a weir structure known as_____________________?
Show answer Hide answer
Answer: C. sill
The top edge or threshold of a weir structure over which liquid flows is called the crest or sill. Water spilling over this structural threshold forms the downstream nappe profile used in flow measurement calculations. A...
Q5. Under what polytropic index value (n) is the work done per unit mass during air compression minimized______________?
Show answer Hide answer
Answer: A. 1
An isothermal compression process maintains constant temperature with a polytropic index of one. Work done during gas compression is directly proportional to the area under the process curve. Isothermal compression requi...
Q6. How does the thermal efficiency of a crankcase-scavenged two-stroke petrol engine compare to a four-stroke engine with an equal compression ratio_____________________?
Show answer Hide answer
Answer: B. lower
Crankcase-scavenged two-stroke petrol engines use the crankcase to compress the incoming air-fuel charge before transfer. This method results in poor scavenging efficiency, allowing fresh mixture to escape directly into...