Problem 6.06 Part A A small button placed on a horizontal rotating platform with
ID: 1535539 • Letter: P
Question
Problem 6.06 Part A A small button placed on a horizontal rotating platform with What is the coefficient of static friction between the button and the platform? diameter 0.324 m will revolve with the platform when it is brought up to a rotational speed of 45.0 rev/min provided Express your answer to three significant figures. the button is no more than 0.143 m from the axis. 0.734 Submit M Answers Gre up Incorrect; Try Again; 3 attempts remaining Part B How far from the axis can the button be placed, without slipping. ifthe platform rotates at 61.0 rev/mi Express your answer to three significant figures. My Answers Give UpExplanation / Answer
normal force N = mg
frictional force fk = uk*N = uk*m*g
centripetal force Fc = m*r*w^2
r = position of btton from center
w = 45 rev/min = 45*2pi/60 = 4.71 rad/s
In equilibri
Fk = Fc
uk*m*g = m*r*w^2
uk = r*w^2/g
uk = 0.123*4.71^2/9.81
uk = 0.278 <<<_------answer
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part B
fk = Fc
uk*m*g = m*r1*w1^2
uk*g = r1*w1^2
w1 = 61 rev/min = 61*(2pi/60) = 6.38 rad/s
0.278*9.81 = r1*6.38^2
r1 = 0.067 m <<<<-----answer