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Tpy6a [65]
3 years ago
7

The 0.4-lb ball and its supporting cord are revolving about the vertical axis on the fixed smooth conical surface with an angula

r velocity of 4 rad /sec. The ball is held in the position b = 14 in. by the tension T in the cord. If the distance b is reduced to the constant value of 9 in. by increasing the tension T in the cord, compute the new angular velocity and the work W1-2 done on the system by T
Physics
1 answer:
solong [7]3 years ago
3 0

Answer:

Explanation:

In the whole process , angular momentum will be conserved because no external torque is acting on the system . The radius of circular path is reduced so angular velocity will be increased

I₁ x ω₁ = I₂ x ω₂

m r₁² x ω₁ = m r₁²ω₂

r₁² x ω₁ =  r₂²ω₂

ω₂ = r₁² x ω₁  /  r₂²

= ( 14 x 14 x 4) / ( 9 x 9 )

= 9.68 rad /s

Work done

= increase in rotational kinetic energy

= 1/2 x I₂ ω₂² - 1/2 x I₁ ω₁²        ( I = m r² )

=  1/2 x .4 x .454 x( 9 x 2.54 x 10⁻² x 9.68 )² - 1/2 x .4 x .454 x( 14 x 2.54 x 10⁻² x 4 )²

=   .4446 - 0.1837

= .261 J .

=

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A dad pushes tangentially on a small hand-driven merry-go-round and is able to accelerate it from rest to a frequency of 18 rpm,
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F = 176.175 N

Explanation:

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radius of merry - go - round = 2.7 m

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