A ballet dancer suddenly folds her outstretched arms. Her angular velocity

A ballet dancer suddenly folds her outstretched arms. Her angular velocity
  1. increases
  2. decreases
  3. remains the same
  4. may increase or decrease

Solution

According to law of conservation of angular momentum, \(I \omega=\text { constant }\)...(i) where, \(I=\) moment of inertia and \(\omega=\) angular velocity. When a ballet dancer suddenly folds her outstretched arms, then her moment of inertia decreases, hence from Eq. (i), we observe that her angular velocity will increases.

Asked in: AP EAMCET 2020 (18 Sep Shift 1)

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