实验步骤如下：

Ⅰ．让同一钢球从斜面上不同的高度由静止滚下，观察木块被撞击后移动的距离．

Ⅱ．让不同质量的钢球从斜面上相同的高度由静止滚下，观察木块被撞击后移动的距离．

回答下列问题：

完形填空

    In some science fiction movies，the robots are just like humans. They help with the housework and do the most 1 jobs.

    Some scientists believe that there will be such robots in the future.2, they agree it may 3hundreds of years. Scientists are now trying to make robots 4people and do the same things as us.

    But robot scientist James White 5. He thinks that it will be 6 for a robot to do the samethings as a person. 7 , it's easy for children to wake up and know where they are. Mr White thinks that robots won't be able to do this. But other scientists disagree. They think that robots will be able to talk to people 8 25 to 50 years.

    Robot scientists are not just trying to make robots look like people. For example, there are already robots 9 in factories. They do simple jobs over and over again. People would not like to do such jobs and would get bored. But robots will 10 get bored.

    In the future，there will be more robots everywhere，and humans will have 11 work to do. New robots will have many different 12. Some will look like humans, and 13 might look like snakes. After anearthquake（地震），a snake robot could help look for people under buildings. That may not seem possible now, but computers, space rockets and even electric tooth brushes 14 impossible a hundred years ago. We never know 15 will happen in the future!