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A coin kept at a distance of 5 cm from t...

A coin kept at a distance of 5 cm from the centre of a turntable of radius `1.5 m` just begins to slip when the turntable rotates at a speed of `90`r.p.m. Calculate the coefficient of static friction between the coin and the turntable `[g = 9.8 m//s^(2)]`

Text Solution

Verified by Experts

Given that, distance at which coin is kept `(r ) = 5` cm
`= 0.05m`, radius of turn table `(R ) = 1.5 Hz`
Limiting force of static friction = Centripital force
`mu_(s)mg = mromega^(2)`
`:. mu_(s) = (romega^(2))/(g) = (r(2pin)^(2))/(g)`
`:. mu_(s) = (4rpi^(2)n^(2))/(g)`
`= (4xx 0.05 xx (3.14)^(2) xx (1.5)^(2))/(9.8)`
`:. mu_(s) = 0.4527`
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Knowledge Check

  • What will be the maximum speed of a car on a road turn of radius 30 m, if the coefficient of friction between the tyres and the road is 0.4? (Take g=9.8m//s^(2) )

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    10.84 m/s
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    9.84 m/s
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    8.84 m/s
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    6.84 m/s

  • What will be maximum speed of a car on a curved road of radius 30 m , If the coefficient of friction between the tyres and the road is 0.4? (g=9.8 m//s^(2))

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    `10.84 m//s`
    B
    `9.84 m//s`
    C
    `8.84 m//s`
    D
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  • A coin just remains on a disc rotating at a steady rate of 180r.p.m .A coin is kept at a distance of 2 cm from the axis of rotationn . The coefficient of fricition between the coin and the disc is _____ [ gg= 9.8 m//s^(2)]

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    C
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