pull - a force that moves something closer, push - a force that moves something away, distance - how far one thing is from another , friction - a force that slows down moving things, position - the place where something is, speed - how fast something moves, force - a push or pull, motion - when something is moving,

G2 Science 21 Simple machines

排行榜

視覺風格

選項

切換範本

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