Question

A block of mass 10 kg is in contact against the

inner wall of a hollow cylindrical drum of

radius 1 m. The coefficient of friction between

the block and the inner wall of the cylinder is

0.1. The minimum angular velocity needed for

the cylinder to keep the block stationary when

the cylinder is vertical and rotating about its

axis, will be :  2 (g 10 m/s )?​

Answer 1

Answer:

PHYSICS

A block of mass 10 kg is in contact against the inner wall of a hollow cylindrical drum of radius 1 m. The coefficient of friction between the block and the inner wall of the cylinder is 0.1. The minimum angular velocity needed for the cylinder to keep the block stationary when the cylinder is vertical and rotating about its axis, will be : (g=10m/s

2

)

November 22, 2019avatar

Om Manasa

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ANSWER

For equilibrium of the block limiting friction

f

L

≥mg

⇒μN≥mg

⇒μmrω

2

≥mg

⟹ω≥

rμ

g

ω

min

=

rμ

g

⟹ω

min

=

0.1×1

10

=10 rad/s

Answer 2

For equilibrium of the block limiting friction

f L ≥mg

⇒μN ≥ mg

⇒μmrω 2 ≥mg

⟹ω ≥ $\sqrt \frac{g}{rμ}$

ω min = √g\rμ

⟹ω min = $\sqrt \frac{10}{0.1 \times 1}$

=10 rad/s