公平买卖是商业行为的准则。在计量买卖行为中,科学、准确的计量又是公平买卖的关键。而这些计量设备、计量过程中蕴含了丰富的物理学知识,我们若熟知这些物理知识,对判断买卖是否公平有很大帮助。我们就以下两个买卖行为来判断一下是否公 Fair trade is the standard of business conduct. In the measurement of trading, scientific and accurate measurement is the key to fair trading. These measuring equipment, measurement process contains a wealth of knowledge of physics, if we know these physical knowledge, to determine the fairness of the sale is very helpful. We will judge whether the following two trading behavior