Question

A figure skater is spinning slowly with arms outstretched. She brings her arms in close to her body and her moment of inertia decreases by 1/2. Her angular speed increases by a factor of

Answer 1

Answer:

the angular velocity increase by a factor of 2

Explanation:

using the law of the conservation of the angular momentum

$L_i = L_f$

where $L_i$ is the inicial angular momentum and $L_f$ is the final angular momentum.

also, the angular momentum can be calculated by:

L = IW

where I is the inertia momentum and the W is the angular velocity.

so:

$I_i W_i = I_fW_f$

we know that $I_f = \frac{1}{2}I_i$ then,

$I_iW_i = \frac{1}{2}I_iW_f$

solving for $W_f$:

$W_f = 2W_i$