A penny is made of the element zinc plated with the element copper; a nickel
is made of a mixture of the elements
nickel and copper. Some isotopes of
various elements are listed below by
their atomic number and mass num-
ber. Use the periodic table on p. 131
to identify which atoms you would
expect to find in the penny, which you
would expect to find in the nickel,
which you would expect to find in
both, and which you would expect to
find in neither coin.​

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,?