题目

School violence ______ much attention of the whole society and people are calling on the government to make laws against it as early as possible. A . drew B . will draw C . has drawn D . was drawing 答案：C如图所示，两端开口的气缸水平固定，A、B是两个厚度不计的活塞，可在气缸内无摩擦滑动，面积分别为S1=20cm2，S2=10cm2，它们之间用一根细杆连接，B通过水平细绳绕过光滑的定滑轮与质量为M=2kg的重物C连接，静止时气缸中的气体温度T1=600K，气缸两部分的气柱长均为L，已知大气压强P0=1×105Pa，取g=10m/s2，缸内气体可看作理想气体；（1）活塞静止时，求气缸内气体的压强；（2）若降低气内气体的温度，当活塞A缓慢向右移动L时，求气缸内气体的温度．