Chapter 11, Problem 72P

An ice skater is preparing for a jump with turns and has his arms extended. His moment of inertia is $1.8 \text{kg}\cdot {\text{m}}^{\text{2}}$ while his arms are extended, and he is spinning at 0.5 rev/s. If he launches himself into the air at 9.0 m/s at an angle of $\text{45}°$ with respect to the ice, how many revolutions can he execute while airborne if his moment of inertia in the air is $0.5 \text{kg}\cdot {\text{m}}^{\text{2}}$ ?