But it's not a big con, because you can set up experiments in free space far from everything, where objects will, in fact, maintain their velocity forever.

但这并不是个反例,因为你可以在一个远离一切的空间里做实验,在那里,物体可以永远保持现有速度

耶鲁公开课 - 基础物理课程节选

scratch Scratch is a program that you can download for free cs50 net and you will see in problem set 0 0 which will be posted on CS50.nettonight under problem sets in both standard and hacker editions, can you do the--can you--it will walk you through the process of getting this software.

你可以免费下载,今天晚上我会在0,放上习套题,这个习题集有两个版本，习题集可以指导你,如何下载这个软件。

哈佛公开课 - 计算机科学课程节选