How many days will it take a spaceship to accelerate from rest to the speed of light (3.0Ã108m/s) with the acceleration g?

Answer is: 354 days.

V = V₀ + g·t.

V - final velocity, V = 3·10⁸ m/s.

V₀ - initial velocity, V₀ = o, because spaceship is in rest.

t - t ime, how long it takes for spaceship to move from one position to another.

g - gravity, g = 9,8 m/s².

t = V:g = 3,06·10⁷s = 510204min = 88503,4hr = 354 days.