A coin is kept at a distance 10 cm from the center of turn
table of radius 1 m just begin to slip, when the turn table rotate at a speed
of 90 r.p.m. calculate the coefficient of static friction between the coin ant
turn table.
Solution:
Given:
Distance of coin from center = r = 10
cm = 0.1
m
Frequency = n = 90 rpm
As frequency is in r.p.m. , we have to convert it in to
r.p.s. or Hz.
The conversion factor is
n
(in r.p.s.) = r.p.m. / 60
= 90 / 60
n = 1.5 Hz
As the coin just begin to slip
Limiting force of static friction = Centrifugal force
µsmg = mrω2
Where µs is a coefficient of static friction
µs = mrω2 /mg
µs = rω2 /g
as ω is an angular velocity = 2πn
therefore,
µs
= r (2πn)2 /g
µs = 4r
π2 n2 /g
µs = 4(0.1)
(3.14)2 (1.5)2 / 9.8
µs = 0.9066
The coefficient of static friction is µs
= 0.9066
The friction coefficient, a fundamental concept in physics and engineering, measures the resistance to motion between two surfaces in contact. It quantifies the ratio of the force required to overcome friction to the force pressing the two surfaces together. Understanding the friction coefficient is crucial in various fields, including materials science, automotive engineering, and manufacturing.
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The friction coefficient, a fundamental concept in physics and engineering, measures the resistance to motion between two surfaces in contact. It quantifies the ratio of the force required to overcome friction to the force pressing the two surfaces together. Understanding the friction coefficient is crucial in various fields, including materials science, automotive engineering, and manufacturing.
ReplyDeletefriction tester