Zero gravity photography

Analysis of test questions: a, set the axle to rotate n times, the length of rope extension, and the height of stuntman rising; correct

B, at this time, the speed of rope elongation, therefore, the linear speed of axle rotation is equal to the speed of rope elongation, and the speed of wheel rotation is equal to the speed of people rising, that is; mistake

C, mechanical energy at the highest point; correct

D, the work done by the steel wire to the actor in this process is equal to the mechanical energy possessed by the actor at the highest point of 2900 J; mistake

So choose AC.

Comments: This topic belongs to the coaxial rotation problem. On the same axis, all points have the same angular velocity, and the ratio of linear velocity of each point is equal to the ratio of radius.