FRICTION IN PHYSICS

BY : MAY RAPIKAID : RSA1C312006

WHAT IS FRICTION ?

APPLICATION OF FRICTION

EXAMPLE PROBLEM

KINDS OF FRICTION

WHAT IS FRICTION ?

FRICTION IS FORCE THAT OPPOSING THE MOTION OF TWO SURFACES IN CONTACT

f = N

APPLICATION OF FRICTION

EXAMPLES…

WHEN WE WALK WHEN THE CAR IS BRAKED

KINDS OF FRICTION

FRICTION STATIC

FRICTION KINETIC

FORCE THAT WORK WHEN THINGS HAVEN’T

NOT MOVED

fs =

FORCE THAT WORK WHEN THINGS MOVED

fk =

EXAMPLE PROBLEM

PROBLEMS

An object with mass = 10 Kg in rough floor pulled by force F = 25 N to the right. If the coefficient of static objects with the floor is 0.2 with kinetic coefficient 0.1. Determine :a. Normal Forceb. Acceleration of the motion of object

mF

SOLUTION

a. Normal Force

N-W = 0 N- mg= 0 N- 10Kg(10m/s2) = 0 N = 100 N

m

N

F

W

f

b. Acceleration (Second Newton Law) Fx = ma f = fk = F-f = ma = 0.1 (100)25-10=10a = 10 Na= 15/10a= 1.5 m/s2