# purpose:  calculate time dilation and mass increase as speed increases
# pre-condition:  velocity as percent of speed of light, 0 to 100
# post-condition:  mass of ship, distance to travel to 4 stars

# import sqrt function for factor equation

# print title and blank line
# ask for velocity as percent of speed of light

# check for negative velocity
#       tell user and use 0.01% as value
# check for velocity 100% or more
#       tell user and use 99% as value
# convert input to percent by dividing by 100
# calculate factor 
# calculate weight of space ship multiplying by factor
#   starting weight  70000.0  kg
# calculate perceived time taken to each of 4 stars, divide by factor
#   Alpha Centauri  4.3 years
#   Barnard's star 6.0 years
#   Betegeuse     309.0 years
#   Andromeda Galaxy  2000000 (2 million) years

# display results, round to 6 places