试题与答案

(10分)质量为10 kg的物体在拉力作用下运动, 求下列四种情况拉力做的功:

题型:计算题

题目:

(10分)质量为10 kg的物体在拉力作用下运动, 求下列四种情况拉力做的功: ( sin370=0.6,cos370="0.8," g=10m/s2)

⑴拉力沿水平方向, 物体在动摩擦因数为0.25的水平地面上匀速移动4 m.

⑵拉力沿水平方向, 物体在动摩擦因数为0.25的水平地面上以2 m / s2的加速度匀加速移动4 m.

⑶用大小为50N,沿水平方向的拉力拉物体在光滑的水平地面上移动4 m.

⑷用大小为50N,方向与水平面成37°角的斜向上的拉力拉物体, 使物体沿水平地面移动4m, 物体与地面间的动摩擦因数为0.25.

答案:

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参考答案:B

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