axis X. In the situation shown on #4a, the
balance and counterbalances are moving
towards axis X until
they reach it – centrifugal force opposes
this move, but past the
axis X picture #4b, ‘au
contraire’, the centrifugal force enforces the
move. In other words,
in a certain period of
the rotation, we are
losing energy due to
centrifugal force; in the
other period, we are
gaining it back. Total
gain/loss of energy is
This similar to centrifuequal to zero.
gal effect: it happens
during coincident rotaBut this is not all. There tion and back-and-forth
is another effect that movements.
affects system performance. I call it the
‘figure skater effect’. Now take a look at picWhen a figure skater is ture #4a again. The
spinning, extending his figure skater is pulling
arms slows him down – his arm in accelerates
contrary to holding his him. Picture #4b, the
arms as close as possi- figure skater extendble, which accelerates ing his arms slows
him down. Here again,
his rotation.
43
in one period we are
losing energy and in
another we are gaining
energy.
As you might notice in
the situation depicted
on #4a, we are losing momentum due to
centrifugal force but
gaining it due to figure skater effect – on
picture #4b, a reverse
centrifugal force is giv-