题目

The United States is full of cars. There are still many families without cars, but some families have two or more. However, cars are used for more than pleasure. They are a necessary part of life. Cars are used for business. They are driven to offices and factories by workers who have no other way to get to their jobs. When salesmen are sent to different parts of the city, they have to drive in order to carry [Z-x-x-k.Com]their products. Farmers have to drive into the city in order to get supplies. Sometimes small children must be driven to school. In some cities school buses are used on2．（1）如图1，重为20N的A物体放在斜面上，请你作A物体所受的重力和对斜面的压力．（2）如图2所示容器内装有一定量的水，水从b孔流出的情景已画出，请在画出图中a与c两孔水流的情景．