A spaceship moves with a uniform velocity u, that is close to the speed of light c, with respect to the ground. The length of the spaceship is L' in the reference of the spaceship itself. One light pulse is emitted from the tail and reaches the head of the spaceship. Find (a) The length of the spaceship in the reference of the ground. (b) How long does it take for this spaceship to pass through the observer on the ground? (c) What is the distance for the light pulse traveled from the tail to the head of this spaceship according to the observer in the reference of the ground?