Should I turn on the power first and then loosen the paper tape? —— Experimental study to verify the conservation of mechanical energy

Verifying the law of conservation of mechanical energy has always been a very important experiment in high school mechanics. Since Jiangsu entered the new curriculum reform in 2005, students have been required to explore, analyze, reason and even design experiments. With the continuous development of education, the experiment to verify the conservation of mechanical energy is also improving. Judging from the first and second points laid at the beginning, it must be 2mm, and now it can be "irrelevant"; In order to reduce the error, the stability of the experimental device is strengthened, and so on. These improvements are the result of continuous exploration by our students and teachers in their usual experiments. In the experimental exploration, the author holds different views on the operation method of "connecting the power supply first, then putting the paper tape": Is it necessary to follow this order? If you loosen the paper tape first and then turn on the power, can you finish the experiment? What role does it play in verifying the conservation of mechanical energy? Below I will talk about some of my own ideas, hoping to get the effect of attracting jade. 1 Analysis of the original explanation of "power must be turned on before releasing the paper tape" In students' experiments, teachers often hold two opinions on the explanation of "power must be turned on before releasing the paper tape": (1) The point timer has just started, the point is unstable, and the paper tape will be released after it is stable. (2) Due to the fast falling speed of objects, it takes time for people to react. If you put the paper tape down and open it again, part of it has fallen off.