Aparticular planet has a moment of inertia of 9.74 × 1037 kg•m2 and a mass of 5.98 × 1024 kg. based on these values, what is the planet’s radius?

Assuming the planet can be treated as a solid sphere,

(9.74 x 10^37 kg-m²) = (2/5)(5.98 x 10^24 kg)R²

R = 6.38 x 10^6 m

Kinetic energy = 1/2mv^2. since the mass is constant we can form a ratio of it's kinetic energy at 60 divided by that at 30 to see ke(60)/ke(30) = +(60^2)/30^2). this may be said to 300% increase.