An ice skater, hasa rotational inertia of I = 4 kg m2, and spins at 2 rad/sec. Her rotational inertia then undergoes a change to 2 kg m2. Which of the following is true?

a. Her angular momentum remains the same
b. Her angular velocity increases
c. Her kinetic energy increases
d. all of above

I say B am i right?

You are right, however, the question lacks depth. Is this an online course?

To determine the correct answer, let's analyze the situation:

The equation for angular momentum is given by L = I * ω, where L is the angular momentum, I is the moment of inertia, and ω is the angular velocity.

Given that the initial moment of inertia (I_initial) is 4 kg m^2 and the initial angular velocity (ω_initial) is 2 rad/sec, we can calculate the initial angular momentum (L_initial):
L_initial = I_initial * ω_initial
L_initial = 4 kg m^2 * 2 rad/sec
L_initial = 8 kg m^2/s

After the change, the new moment of inertia (I_final) is 2 kg m^2. To find the new angular velocity (ω_final), we can rearrange the equation: L_final = I_final * ω_final, and solve for ω_final.

Since angular momentum is conserved (L_initial = L_final), we have:
L_initial = L_final
I_initial * ω_initial = I_final * ω_final
4 kg m^2 * 2 rad/sec = 2 kg m^2 * ω_final
8 kg m^2/s = 2 kg m^2 * ω_final
ω_final = 8 kg m^2/s / 2 kg m^2
ω_final = 4 rad/sec

Now let's compare the initial and final angular velocities:

ω_initial = 2 rad/sec
ω_final = 4 rad/sec

Since ω_final is greater than ω_initial, we can conclude that the angular velocity increases after the moment of inertia is changed.

Therefore, the correct answer is b. Her angular velocity increases.