Answer:
a) its frequency
Explanation:
The color of visible light depends only on its frequency, not on the amplitude. In fact, the visible light spectrum can be classified into different colors according to the different frequencies:
Violet: 680-790 THz
Blue: 620-680 THz
Cyan: 600-620 THz
Green: 530-600 THz
Yellow: 510-530 THz
Orange: 480-510 THz
Red: 405-480 THz
And the color of the light has nothing to do with the amplitude of the wave. Therefore, the correct answer is
a) its frequency
To solve this problem it is necessary to apply the concepts related to the conservation of the Gravitational Force and the centripetal force by equilibrium,


Where,
m = Mass of spacecraft
M = Mass of Earth
r = Radius (Orbit)
G = Gravitational Universal Music
v = Velocity
Re-arrange to find the velocity



PART A ) The radius of the spacecraft's orbit is 2 times the radius of the earth, that is, considering the center of the earth, the spacecraft is 3 times at that distance. Replacing then,


From the speed it is possible to use find the formula, so



Therefore the orbital period of the spacecraft is 2 hours and 24 minutes.
PART B) To find the kinetic energy we simply apply the definition of kinetic energy on the ship, which is



Therefore the kinetic energy of the Spacecraft is 1.04 Gigajules.