Question

a. What is the combined angular momentum of the masses?

b. If she pulls her arms in to 0.15 m, what is her linear speed if the angular momentum remains constant?

Answer 1

3. Jessica stretches her arms out 0.6 m from the center of her body while holding a 2 kg mass in each hand. She then spins around on an ice rink at 1.1 m/s.

Answer 2

Angular momentum L = I x omega
where I : Moment of inertia
omega : angular velocity

I = m r^2
M : mass
r : radius..

Answer 3

here we have to keep in mind that if we can neglect any form of friction force, then we can apply this equation:
\[I\omega = {\text{const}}\]
namely the product between the angular momentum and the angular speed has to remain constant. So we can write the subsequent conservation equation:
\[{I_1}{\omega _1} = {I_2}{\omega _2}\]
where the subscript \(1\) refers to before pulling the arms, and the subscript \(2\) refers to after she pulled her arms. Now after she pulled her arms, its angular momentum \(I_2\) is less than \(I_1\), so in order to get the conservation, necessarily we have: \(\omega_2>\omega_1\), so what can you conclude?