[7 / 1 / ?]
This WAS a homework question on mastering physics, I already got it wrong according to that program:
You're working on a new high-speed rail system. It uses 6000-horsepower electric locomotives, getting power from a single overhead wire with resistance 15 mΩ/km, at 29 kV potential relative to the track. Current returns through the track, whose resistance is negligible. Energy-efficiency standards call for no more than 3% power loss in the wire.
How far from the power plant can the train go and still meet this standard?
What do you guys come up with? Mastering physics claims it's 380km. I'm getting answers much greater than the diameter of the earth. Like 4.18 x 10^5 km. I want to see if mastering physics fucked up here.
You're working on a new high-speed rail system. It uses 6000-horsepower electric locomotives, getting power from a single overhead wire with resistance 15 mΩ/km, at 29 kV potential relative to the track. Current returns through the track, whose resistance is negligible. Energy-efficiency standards call for no more than 3% power loss in the wire.
How far from the power plant can the train go and still meet this standard?
What do you guys come up with? Mastering physics claims it's 380km. I'm getting answers much greater than the diameter of the earth. Like 4.18 x 10^5 km. I want to see if mastering physics fucked up here.
