题目

下列关于动能的说法正确的是（    ）                                                                           A．  物体的质量不变，速度增大到原来的2倍，则动能增大到原来的2倍    B．  物体的速度不变，质量增大到原来的2倍，则动能增大到原来的2倍    C．  汽车在水平公路上加速行驶时，动能的增加量等于牵引力所做的功    D．  在物体保持动能不变的过程中，一定没有任何力对物体做功          阅读理解。阅读下面这篇短文，然后判断句子是否与短文内容相符，相符的用“T”表示，不相符的用“F”表示。Last WeekendI’m Zhang Peng. I had a great day yesterday. It was a sunny Saturday. The sun was shining. The sky was blue. I got up at 7 in the morning. I had some bread and milk for breakfast and did my homework. Then I went to Zhongshan Park with my classmates. It is near our school, so we went there on foot. The park is very beautiful. We had lunch on the grass. Then I flew kites with Oliver. Sarah, Amy and Chen Jie played hide and seek. We were all very happy. We went back at 4:30. After I got home, I helped my mother with housework. I had a good time yesterday. What about you? Tell me something about your weekend.【1】Yesterday was a sunny day. （______）【2】Zhang Peng had breakfast in the park. （______）【3】Zhang Peng and his classmates went to the park on foot. （______）【4】Sarah flew kites with Oliver. （______）【5】Zhang Peng did his homework before he went to the park. （______）