You rub a clear plastic pen with wool, and observe that a strip of invisible tape is attacted to the pen. assuming that the pen has a negative charge, which of the following could be true? select all that apply. :

a. the tape might be negatively charged.

b. the tape might be positively charged.

c. the tape might be uncharged.

d. there is not enough information to conclude anything.

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,?