physics #3, (angular momentum) PLEASE BE MY HERO!!!!!!?

Question

2.
Assuming a hypothetical planet to be a uniform sphere, of mass 3.0E24 kg, radius 5.0E6m and 1.4E8km from the sun.

a- estimate the kinetic energy of this hyphthetical plante due to its 24 hour rotation about its axis

b- estimate the kinetic energy of this hypothetical planet with respect to the sun due to its yearly 365 day revolution

c- estimate the kinetic energy of this hypothetical planet with respect to the sun as the sum of the kinetic energies resulting in part a and part b

Answer 1

a)first need velocity of planet. do (2pi(5x10^6))/(24x60^2)
=363.61m/s
KE=.5mv^2
KE=1.98x10^29
b)need velocity again ((1.4x10^11+5x10^6)2pi)/(365x24x60^2)
=27894m/s
KE=1.167x10^33
c)KE=1.167x10^33

Answer 2

Angular momentum = Inertia x omega (rad/s) Inertia = mr^2 = fifty one x 3.2^2 = 522.24 kg-m^2 circumference = 3.2 x 2 x pi = 20.a million m 20.a million/17 = a million.1827 revs in line with sec a million.1827 x (2 x pi) = rad/s = 7.431 Angular momentum = 522.24 x 7.431 = 3880.seventy seven kg-m^2/s