code: def froude_number(speed, length):
      
      g = 9.80665  # conventional standard value m/s^2
      Fr = speed / np.sqrt(g * length)
      return Fr
docs: Froude number utility function that return Froude number for vehicle at specific length and speed.
  
      :param speed: m/s speed of the vehicle
      :param length: metres length of the vehicle
      :return: Froude number of the vehicle (dimensionless)