题干

一定质量的理想气体被活塞封闭在汽缸内,如图所示水平放置 . 活塞的质量 m=20kg ,横截面积 S=100cm2 ,活塞可沿汽缸壁无摩擦滑动但不漏气,开始使汽缸水平放置,活塞与汽缸底的距离 L1=12cm ,离汽缸口的距离 L2=4cm. 外界气温为 27 ,大气压强为 1.0×105Pa ,将汽缸缓慢地转到开口向上的竖直位置,待稳定后对缸内气体逐渐加热,使活塞上表面刚好与汽缸口相平,已知 g=10m/s2 ,求:
①此时气体的温度为多少;
②在对缸内气体加热的过程中,气体膨胀对外做功,同时吸收 Q=390J 的热量,则气体增加的内能 U 多大.
上一题 下一题 0.0难度 选择题 更新时间:2016-06-02 10:16:10

答案(点此获取答案解析)

解: 当气缸水平放置时, p0=1.0×105P

同类题2

根据短文内容, 从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    While serious training is important for all dogs, playtime is just as important. ____ Use these games to help teach your dog how to play.

1). Hide and Seek

    Hide and seek isn't just for kids. Dogs can really enjoy this game. Pick up one of your dog's favorite toys or treats. Tell your dog to stay. ____ When you are ready, call your dog to come to you. If possible, squeak (使吱吱叫) the toy or shake the treats. Reward your dog with praise and the toy or treat when she finds you.

2). Fetch

    Many dogs have a natural ability to fetch. Other dogs can be taught how. ____ Play indoors with a soft toy or outdoors in a fenced-in area with a ball or disc. For dogs that really love to run, try this game of fetch!

3). Find the Treat

    Dogs have superior senses of smell, and most love to use their noses to find food. Let your dog use her brain and her nose to find hidden goodies. First, have your dog stay out of sight. Then, hide her favorite treats in various places around the room. ____ If help is needed, you can lead her around or point to areas for her to explore.

Whatever the game, safety comes first! Remember to watch your dog for signs of exhaustion or overheating when you are playing. Stop if your dog seems tired or shows signs of anxiety. ____ When other dogs or people are around, it may create a dangerous distraction.

A. Then, go to find a good hiding place.

B. Try different games to see which your dog responds to best.

C. A good game of fetch can be played almost anywhere.

D. You can include games in training as well.

E. Also be aware of your surroundings when playing with your dog.

F. Encourage your dog to play with other dogs.

G. Bring your dog back in and tell her to “go find!”