Question

A disc rotating about its axis with angular speed $\omega_{0}$ is placed lightly (without any translational push) on a perfectly frictionless table. The radius of the disc is R. Let vA, vB and vc be the magnitudes of linear velocities of the points A, B and C on the disc as shown. Then

• A. vA>vB> vc
• B. vA < vB < vc
• C. vA = vB< vc
• D. vA = vB> vc

Answer 1

Answer: (D)

vA = vB> vc

Answer 2

Velocity at point on the disc, $v = r\omega$

$\therefore v_{A} = R\omega_{0}$

$v_{B} = R\omega_{0}$

$v_{C} = \frac{R}{2}\omega_{0}$

$\therefore v_{A} = v_{B} > v_{C}$