Solved question paper for EME May-2014 (B-TECH 1st-2nd)

Solved Question Paper

Elements of mechanical engineering May-2014

PTU • B-TECH • Information Technology • 1st-2nd • May-2014

elements of mechanical engineering previous year question papers on BRpaper are organized for students of Punjab Technical University’s Bachelor of Technology program, 1st-2nd semester. This section makes it easier to browse subject-wise old question papers for elements of mechanical engineering, so students can review how questions are typically framed in past exams and get a sense of the exam pattern. Many students search for elements of mechanical engineering question bank while preparing for exams, and this page is built to support exactly that kind of subject-wise browsing and revision. BRpaper is not the official website of Punjab Technical University or any institution, and it does not publish official notices or academic updates.

Solved Questions

Solved
  1. A constant mass goes through a process where 100 W of heat transfer comes in and 100 W of work leaves. Does the mass change state?
    Short Answer 2 Marks May-2014 • PTU B-TECH
  2. An inventor has developed a refrigeration unit that maintains the cold space at -10°C while operating in a 25°C room. A coefficient of performance of 8.5 is claimed. How do you evaluate this?
    Short Answer 2 Marks May-2014 • PTU B-TECH
  3. A reversible process adds heat to a substance. If T is varying, does that influence the change in s?
    Short Answer 2 Marks May-2014 • PTU B-TECH
  4. For the same compression ratio and heat rejection, compare Otto cycle and Diesel cycle on P-v and T-s diagrams.
    Short Answer 2 Marks May-2014 • PTU B-TECH
  5. For the same peak pressure, peak temperature and heat rejection, compare Otto cycle and Diesel cycle on P-v and T-s diagrams.
    Short Answer 2 Marks May-2014 • PTU B-TECH
  6. In the absence of any friction and other irreversibilities, can a heat engine have an efficiency of 100 percent?
    Short Answer 2 Marks May-2014 • PTU B-TECH
  7. Define the following: i) Resilience, ii) Proof resilience, iii) Modulus of resilience.
    Short Answer 2 Marks May-2014 • PTU B-TECH
  8. For a material, Young’s modulus is given as 1.2 x 10^5 N/mm^2 and Poisson’s ratio is 0.25. Calculate the bulk modulus.
    Short Answer 2 Marks May-2014 • PTU B-TECH
  9. Draw neat sketches of any two inversions of double slider kinematic chain.
    Short Answer 2 Marks May-2014 • PTU B-TECH
  10. Explain the terms reversibility and irreversibility as applied to lifting machines.
    Short Answer 2 Marks May-2014 • PTU B-TECH
  11. A system containing 0.2 m^3 of air at a pressure of 4 bar and 160°C expands isentropically to a pressure of 1.06 bar and this gas is heated at constant pressure till the enthalpy increases by 65 kJ. Calculate the work done. Now imagine that these processes are replaced by a single reversible polytropic process producing the same work between initial and final state; find the index of expansion in this case. Take c_p = 1.005 kJ/kg-K.
    Long Answer 8 Marks May-2014 • PTU B-TECH
  12. A reversible heat engine operates under two environments. In the first it draws 12000 kJ/s from a thermal source at 400°C and in the second environment, it draws 25000 kJ/s from a thermal source at 100°C. In both the operations, the engine rejects heat to a thermal sink at 20°C. Determine the operation in which the engine delivers more power.
    Long Answer 8 Marks May-2014 • PTU B-TECH
  13. Verify the statement “The efficiency of an irreversible engine is always less than the efficiency of reversible one operating between the same two thermal reservoirs”.
    Long Answer 8 Marks May-2014 • PTU B-TECH
  14. Air at 105 m/s and 1.25 kg/m^3 enters a gas turbine at the inlet area of 0.05 m^2. The air stream exits from the gas turbine at 135 m/s and 0.67 kg/m^3. During the flow process, the air loses 27 kJ/kg of heat and its specific enthalpy comes down by 145 kJ/kg. Determine: a) the mass flow rate of air through the turbine, b) the turbine exit area, c) the power developed by the turbine.
    Long Answer 8 Marks May-2014 • PTU B-TECH
  15. Define inequality of Clausius and entropy of a system. Show that for an irreversible process ds > dQ/T.
    Long Answer 8 Marks May-2014 • PTU B-TECH
  16. A heat engine is supplied with 278 kJ/s of heat at a constant fixed temperature of 283°C and the heat rejection takes place at 5°C. The following results were reported: a) 208 kJ/s of heat rejected b) 139 kJ/s of heat rejected c) 70 kJ/s of heat rejected. Classify which of the results report a reversible cycle, irreversible cycle or impossible cycle.
    Long Answer 8 Marks May-2014 • PTU B-TECH
  17. Show that the efficiency of a Brayton cycle depends only on the pressure ratio.
    Long Answer 4 Marks May-2014 • PTU B-TECH
  18. In an air standard Brayton cycle, air enters the compressor at 300 K and 1 bar. The pressure ratio is 8 and the maximum allowable temperature is 1300 K. Determine the temperature and pressure at each state of the cycle, compressor work, and turbine work per kg of air and cycle efficiency.
    Long Answer 4 Marks May-2014 • PTU B-TECH
  19. In a lifting machine an effort of 98.2 N raised a load of 1000 N and an effort of 498.2 N raised a load of 6000 N. Find the law of machine. Find what effort is required to lift a load of 10000 N? Find also the maximum mechanical advantage.
    Long Answer 4 Marks May-2014 • PTU B-TECH
  20. Explain differential pulley block arrangement with a neat sketch and find expression for velocity ratio.
    Long Answer 4 Marks May-2014 • PTU B-TECH
  21. Prove that the maximum stress induced in a body due to sudden applied load is twice the stress induced when the same load is applied gradually.
    Long Answer 4 Marks May-2014 • PTU B-TECH
  22. A weight W falls through 1 cm on a collar attached at the bottom of a vertical bar. The maximum instantaneous extension in the bar is 0.002 mm for a length of 3 m. The area of cross-section of the bar is 6 cm^2. Find the corresponding stress and the weight W. Take E = 200 GPa.
    Long Answer 4 Marks May-2014 • PTU B-TECH
  23. Discuss working of a crank and slotted lever type of quick return mechanism with a neat sketch and explain its working.
    Long Answer 4 Marks May-2014 • PTU B-TECH
  24. Derive an expression for thermal efficiency of an Otto cycle and prove that for maximum work, compression ratio should be 1.25^(?)
    Long Answer 4 Marks May-2014 • PTU B-TECH

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01 Where can I find elements of mechanical engineering previous year question papers for Bachelor of Technology, 1st-2nd semester?

This page lists elements of mechanical engineering question papers uploaded for Punjab Technical University Bachelor of Technology, 1st-2nd semester, organized for subject-wise browsing where available.

02 Are these official Punjab Technical University question papers?

BRpaper is not the official website of Punjab Technical University. These papers are shared for reference and revision purposes only and are not official university material.

03 How can previous year elements of mechanical engineering papers help in exam preparation?

Reviewing past papers can help you understand how questions are typically framed, notice commonly repeated topics, and get a sense of the exam pattern before your own exam.

04 What kind of topics does elements of mechanical engineering usually cover?

The question papers here relate to the official elements of mechanical engineering syllabus set by the university for this course and semester.

05 Does this page include a elements of mechanical engineering question bank or solved answers?

This page focuses on providing access to the previous year question papers themselves. A separate question bank or solved answers may not be available for every paper.

06 Can I find papers for other subjects in the same Bachelor of Technology?

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