题目

In the future your automobile will run on water instead of gas! You will be able to buy a supercomputer that fits in your pocket! You might even drive a flying car! For each prediction that has come true today, several others have missed by a mile. Many of these predictions didn’t consider how people would want to use the technology. Or if people really needed it in their lives or not. Let’s look at some predictions from the not-too-distant past. Robot Helpers Where’s the robot in my kitchen? Nowhere, of course. And he’s probably not coming anytime soon. Robots do exist today, but most达·芬奇是意大利著名的画家，他曾经设计了一个“永动机”，如图所示。他设计时认为右边的钢球比左边的钢球离轮心更远些，在两边不均衡的作用力下，轮子会沿箭头方向转动不息。你认为达·芬奇的“永动机”        （选填“能”或“不能”）永远转动。你的判断理由是                  。