This document provides information about a mechanical engineering course on engineering mechanics taught by Professor Devaprakasam Deivasagayam. The course covers topics like friction forces, static and kinetic friction, and their importance in engineering applications. It aims to enable students to solve problems involving frictional forces and design devices that utilize high and low friction. The document gives examples of how friction helps objects remain stationary or allows for controlled motion in applications like walking, driving, sports, and ice skating. It also explains the concepts of static friction, kinetic friction, and the difference between the two.

1. DEVAPRAKASAM DEIVASAGAYAM
Professor of Mechanical Engineering
Room:11, LW, 2nd Floor
School of Mechanical and Building Sciences
Email: devaprakasam.d@vit.ac.in, dr.devaprakasam@gmail.com
ME202: Engineering Mechanics (3:1:0:4)
Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933

2. Objective and Outcomes
Learning Objectives
• Need for Friction Force in Engineering Applications.
• Friction coefficients of materials.
• Importance of static and dynamic friction forces.
Learning Outcomes
• Enable to solve frictional force associated engineering
problems.
• Enable to Design high friction and low friction devices
used in various engineering applications

3. Friction Force
 Responsible for keeping the object on surface, without
slip.
 Man walking on the floor without falling/ slipping
 Moving car or automobile vehicle on the road without
skidding.
 Spike underneath of Athletes / Sportsman Shoe give
more control
 Ice Skating – controlled motion of skaters

4. Static or Dynamic?
• Static Friction
• Kinetic Friction
tanφs= Fm/N=µs N/N
tanφk=Fk/N=µk N/N
P
N
Ff
W
Ff
P
Motion
Fm
Fk

5. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

6. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

7. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

8. Static or Dynamic?
P
N
Ff
W
W
θ
θ
N
W sinθ
W cosθ
N cosθ
N sinθ
Case 1: Ff>P, (µsN>P) No Motion
Case 2: Fm=P, (µsN=P) Impending Motion
Case3: Fk<P, (µkN<P) Motion
Case 1: Ff>P, (µs Nsinθ>P) , No Motion
Case 2: Fm=P, (µs Nsinθ=P), Impending
Motion
Case3: Fk<P, (µk Nsinθ<P) Motion,
θ

9. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

10. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

11. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

12. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

13. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

14. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

15. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

16. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

17. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

18. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

19. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

20. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

21. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction
θ
θ
y
x
F
N
Maximum Friction Force

22. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

23. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction
y
θ
θ
x
F
N
Maximum
Friction Force
Actual Friction Force

24. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

25. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction

26. Devaprakasam D, Email: devaprakasam.d@vit.ac.in, Ph: +91 9786553933
Dry Friction