A new high speed rail system uses 6000 horsepower electric cars which get their power from 25 kV overhead wire with resistance 15 ohm. current returns through the track, whose resistance is negligble. what is the maximum range of the train

 L = 6944.44 m

Explanation:

For this exercise, let's look for the current consumed by each train drop

         P = I V

         I = P / V

         I = 6000/25000

         I = 0.24 A

This is the current consumed by each train down.

Let's calculate the current that carries the cables

         V = I R

         I₂ = V / R

         I₂ = 25000/15

         I₂ = 1666.67 A

As the resistance value increases linearly with the length of the cable, let's use a rule of proportions, to find the total length

         L = 1666.67 (1 / 0.24)

         L = 6944.44 m

This is the length that a downturn can travel before the current is insufficient to move it