ME4102: Describe the law’s of Mechanics and Simple Harmonic Motion: Mechanical Engineering, NUS, Singapore

  Answer all the Questions:
1. Describe the law’s of mechanics and simple harmonic motion

2. Define ‘frictional force’. Explain how friction is both desirable and undesirable in engineering applications. Describe the friction types, laws of dry friction, angle of friction and coefficient of friction

3. How will you distinguish between static friction and dynamic friction?

4. What is a wedge? State its uses and the method of solving the problems on friction

5. A block rests on a place at 12° to the horizontal. The weight is 80N and the coefficient of friction is 0.4. Calculate force that will just make it slide up the plane

6. A mass of 10 kg accelerates at 5 m/s2 for 10 seconds. Calculate (i). force-producing acceleration (ii). change in velocity (iii). change in momentum (iv). impulse

7. The load on a lever is 2 KN and acts 20 mm from the fulcrum. The effort is 200 mm from the fulcrum. Assuming 100% efficiency, calculate the effort

8. 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: (i) Velocity ratio (ii) Mechanical advantage (iii) Effect of friction (iv) Efficiency at this load

9. A beam has a solid circular cross-section 50 mm outer diameter. Calculate the second moment of area about a diameter

10. A beam has a hollow rectangular cross-section 100 mm wide and 150 mm deep with a thickness of mm for all side. Find the second moment of area

11. A beam has a hollow circular cross-section 60 mm outer diameter and 30 mm inner diameter. Calculate the second moment of area about a diameter

12. A beam has a rectangular cross-section 80 mm wide and 120 mm deep. Find the second moment of area about the axis through the middle parallel to the short edge

13. What is a machine? Explain the difference between a simple machine and a
compound machine

14. A certain weight lifting machine of velocity ratio 30 can lilt a load of 1500 N with the help of 125 N effort. Determine if the machine is reversible

15. In a lifting machine. whose velocity ratio Is 50. an effort of 100 N is required to lift a load of 4 kN. Is the machine reversible? If so. what effort should be applied so that the machine is at the point of reversing?

16. What do you understand by the term ‘acceleration? Define positive acceleration and negative acceleration

17. Distinguish clearly between ‘mass’ and ‘weight’. Define the terms ‘centre of gravity

18. Describe the basic mechanical concepts and types of links

19. Describe the classification of kinematic pairs

20. Describe any two Inversion of Mechanism with relevant schematics