How to get angular momentum?

Question

In this experiment, a disk was dropped on a rotary motion sensor. Disk 1 has a Moment of Intertia (I_a) at 3996x10^-8 . Another was dropped that has a Moment of Inertia (I_b) of 1064x10^-6 . The initial angular velocity is

-25.88 [rad/s] and final angular velocity of -6.31 [rad/s].

What are the Initial angular momentum (L_i) and the final angular momentum (L_f)?

Answer 1

The initial angular momentum (Li) is given by L_i = Iω

where I is the moment of inertia and ω is the angular velocity.

For Disk 1:

L_i = I_aω = (3996x10^-8 kg m^2) (-25.88 rad/s) = -0.01034 kg m^2/s

For the disk2:

L_i = I_bω = (1064x10^-6 kg m^2) (-25.88 rad/s) = -0.0276 kg m^2/s

The final angular momentum (L_f) can be calculated using the same formula:

L_f = Iω

For Disk 1:

L_f = I_aω = (3996x10^-8 kg m^2) (-6.31 rad/s) = -0.00252 kg m^2/s

For the disk 2:

L_f = I_bω = (1064x10^-6 kg m^2) (-6.31 rad/s) = -0.00671 kg m^2/s