Feynman problem: (a) evaluate the acceleration of gravity at the earth's surface lg in units of lightyears. (b) if an isolated spaceship accelerates at such a rate that its occupants feel a constant acceleration equal to that of gravity at the earth's surface, and does so for a period of 5.00 years. as measured by a stationary (unaccelerated) observer who is at rest with respect to the ship at t = 0, how far has the ship gone, and how fast ū is it traveling, at the end of this time?