. A train with a proper length or length at rest of 200 m is traveling at a relativistic speed. If the  train has a contracted length of 100 m, what is the speed of the train? Express your answer in  terms of c, the speed of light?

1. You are an observer in a 100-m long spacecraft traveling from the earth to the moon at 0.8c. (a)What is the proper length of the spacecraft? (b) For a proper time interval of 1 sec., the relativistic time interval for the spacecraft measured from the earth reference frame would be: (c)Time dilation does not apply to all time-dependent physical and biological processes. T/F? (c) What is the relativistic length, DL measured from the reference frame of earth? (d) An APOLLO crew left a flat mirror reflector on the surface of the moon (for all you deniers out there, in the 50th anniversary year of APOLLO 11!). If the average surface-to-surface distance from the earth to the moon is 3.83 x 10^8 m, then how long does it take moonlight to reach earth?

2. Please help me answer these questions, well explained. A spacecraft travelling at a speed of 0.95 c goes from the planet Jupiter to the planet Pluto. A. If an observer on planet Jupiter measures the length of the vessel as 55 m, how long is it when it is stationary? B. A monkey inside the ship has a pulse of 116 beats/min when he is on the earth. What is his pulse inside the ship?