问题
问答题
用100N的水平向右的力推着重300 N的木箱在地面上做匀速直线运动．求：木箱受到的摩擦力的大小和方向．
答案
根据二力平衡的条件，可判断摩擦力和100N水平推力是平衡力，则：f=F=100N，方向水平向左．
答：木箱受到的摩擦力的大小为100N，方向为水平向左．
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用100N的水平向右的力推着重300 N的木箱在地面上做匀速直线运动．求：木箱受到的摩擦力的大小和方向．
根据二力平衡的条件，可判断摩擦力和100N水平推力是平衡力，则：f=F=100N，方向水平向左．
答：木箱受到的摩擦力的大小为100N，方向为水平向左．
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小题1: for his magic shows. Now everyone is interested in magic. We all want to know how to do a trick! From 小题2: to coins and to rubber bands (皮筋), it seems that anything can be used in a trick. Liu didn't go to any magic schools. He learned by 小题3:. He practices hard. Now he is a great magician. When Liu was seven, he saw a coin trick in a big store. At that moment Liu decided to learn magic. Liu practiced hard to 小题4: his skills. Then one day he put on a show for his class. "There was the surprise on everyone's face. It was cool." Liu still 小题5: hard at magic today. He may spend three years working on a new show. |