【判断题】保守力做功与势能的关系是 保守力做功等于势能增量的负值(或保守力做功等于势能的减少量 ) 。
【单选题】Under the floating exchange rate system, a fall in the market price of a currency is called:
【单选题】The young fellow standing under the tree, ____ is good at English, is from Beijing.
【判断题】保守力做功等于势能增量的负值,保守力做正功势能减小