mee202 engineering mechanics l9-10
TRANSCRIPT
DEVAPRAKASAM DEIVASAGAYAMProfessor of Mechanical Engineering
Room:11, LW, 2nd FloorSchool of Mechanical and Building Sciences
Email: [email protected], [email protected]
ME202: Engineering Mechanics (3:1:0:4)
Devaprakasam D, Email: [email protected], Ph: +91 9786553933
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
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
Static or Dynamic?
• Static Friction • Kinetic Friction
tanφs= Fm/N=µs N/Ntanφk=Fk/N=µk N/N
P
N
Ff
W
Ff
P
Motion
Equilib
rium
FmFk
Static or Dynamic?
P
Ff
P
N
Ff
W
W
θ
θN
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
Devaprakasam D, Email: [email protected], Ph: +91 9786553933
Dry Friction
θ
θ
y
x
F
N
Maximum Friction Force
Devaprakasam D, Email: [email protected], Ph: +91 9786553933
Dry Frictiony
θ
θ
x
F
N
Maximum Friction Force
Actual Friction Force
