DISCUSSION OF THE WORK DONE BY FRICTION FORCE ONCURVED ORBITS

The problem of friction work is common in physics teaching in universities and middle schools, and it is also a key and difficult point in physics teaching. This paper derives the expression of the friction work to object on an arbitrary rough curved orbit, and takes quarter arc track and parabolic track as examples, analyzing the characteristics of the velocity, support force, and friction work with angle during the sliding process, discussing the impact of the dynamic friction factor on the three, and calculating dynamic friction factor which makes the object exactly stops at the lowest point of the two tracks above, to enrich students' understandings.