Changes in energy must hold in all frames of reference.
The reason it doesn't take any more effort to walk at 5mph on a 100mph train is because when you accelerate, you're absorbing energy from the train. The train slows down slightly, due to conservation of momentum.
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Changes in energy must hold in all frames of reference. The reason it doesn't take any more effort to walk at 5mph on a 100mph train is because when you accelerate, you're absorbing energy from the train. The train slows down slightly, due to conservation of momentum.