A ball is dropped from rest from height h above the ground in frame S (the Earth's frame). Another frame S' with the Earth's frame is moving upwards with constant speed u relative to the Earth. In frame S', the ball has initial downward speed u. Pertaining to the change in kinetic energy (ΔK) of the ball from release to just before hitting the ground as measured in frames S and S' separately, which one of the following is correct?
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