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> 质量为1.0kg的小球从高20m处自由下落到软垫上，反弹后上升的最大高度为5.0m，小球与软垫接触的时间为1.0s，在接触时间内小球受到合力的冲量为（空气阻力不计，g取10m/s 2）（　　） A．40N•s 方向向上 B．40N•s 方向向下 C．30N•s 　方向向上 D．30N•s 方向向下

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发布时间：2024-09-12

质量为1.0kg的小球从高20m处自由下落到软垫上，反弹后上升的最大高度为5.0m，小球与软垫接触的时间为1.0s，在接触时间内小球受到合力的冲量为（空气阻力不计，g取10m/s ²）（　　）

A．40N•s 方向向上 B．40N•s 方向向下

C．30N•s 　方向向上 D．30N•s 方向向下

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提问用户：8m***sle

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