Help me with this please

Adiver in midair has an angular velocity of 6.0 rad/s and a moment of inertia of 1.2 kg·m2. he then pulls is arms and legs into a tuck position and his angular velocity increases to 12 rad/s. the net external torque acting on the diver is zero. what is his moment of inertia in the tuck position?

Which compound is held together by the electrostatic force between two ions? a. co2 b. cci4 c. h2s d. mgf2

How does the entropy of steam compare to the entropy of ice?