Was it on a cable? If so, was one machine a single pulley and one a double pulley?

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Some machines are in kilograms and some are in pounds, either way they're only labeled half the time. Some weight amounts are measured per hand and others write the total weight. Pulley systems also play a big role in the physics of how machines work. Short version is more moving pulleys means less strength required for the same weight. If you're legitimately asking, it's probably one of those three things: weight units, one-hand vs two-hand calibration, and pulley physics.

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Physics

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