题型:问答题 简答题 如图所示,劲度系数为k=40.0N/m的轻质水平弹簧左端固定在壁上,右端系一质量M=3.0kg的小物块A,A的右边系一轻细线,细线绕过轻质光滑的滑轮后与轻挂钩相连,小物块A放在足够长的桌面上,它与桌面的滑动摩擦因数为0.2,最大静摩擦力等于滑动摩擦力。滑轮以左的轻绳处于水平静止状态,弹簧的长度为自然长度。现将一质量m=2.0kg的物体B轻挂在钩上,然后松手,在此后的整个运动过程中,求:(1)小物块A速度达到最大时的位置;(2)弹簧弹性势能的最大值;(3)小物块A克服摩擦力所做的功。 查看答案
题型:问答题 简答题 用方框中所给单词的适当形式填空。easy, lose, disagree, develop, soldier, break1. The weather changed a lot this winter. People_________caught a cold.2. Sometimes young children have_________and decide not to talk to each other.3. Last year his father_________his job. Now his family is very poor.4. The whole world is surprised at China's fast_________.China is becoming stronger and stronger.5. There were many good_________in China, like Dong Cunrui, Huang Jiguang and so on.6. They have stayed angry for years about a small problem, so they have_________, off a friendship. 查看答案