For a fiber-reinforced composite, the efficiency of reinforcement η is dependent on fiber length l according to where x represents the length of the fiber at each end that does not contribute to the load transfer. what length is required for a 0.62 efficiency of reinforcement, assuming that x is 0.61 mm?

During the experiment if you could triple the breakaway magnetic force with all other quantities left unchanged, what is the new value for the critical velocity if it was v0 (initial velocity), initially? (b) now if you halved the radius with all other quantities left unchanged, what is the new critical velocity if it was v0 (initial velocity), initially? (c) if during the experiment, critical velocity quadrupled with all other quantities left unchanged, what is the new breakaway force if its magnitude was initially f0,?