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$1,050
力的方向與大小變換實驗
有大、中、小三層設計輪軸盤，附三腳台支持鐵架
配件：20克(等量)砝碼 6個(附繩)
plastic pulley with 3 different diameters mounted on pin bearings and attached to a steel stand. 6 hooked 20g masses included.
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