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Question 7If friction can be neglected, all objects drop to the earth with the same acceleration, independent of their mass. What is, in a nutshell, the main reason for this fact? Answer: Inert mass and gravitational mass are proportional to each other. There is a general problem with such items, where you ask for a written statement. The question is, how valid the grading is. Test experts always propose to use multiple choice items. I hesitated to do so because I am not sure if students will recognise the correct answer among some false statements. Anyhow, my own experience tells me that our findings are typical. So we have a severe teaching/learning problem at hand. Our students do not have a good explanation for a basic fact: that all objects, a leave or feather and a Jumbo are dropping down to earth with the same acceleration. |
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