21. Perky rides at different radial distances
from the center of a turntable that rotates
at a fixed rate. His distances and tangential
speeds at three different locations are as
follows.
(A) r = 15 cm, v = 7.5 cm/s
(B) r = 10 cm, v = 5.0 cm/s
(C) r = 5.0 cm, v = 2.5 cm/s
W
a. Rank from greatest to least, Perky's an-
gular momenta.
b. Rank from greatest to least, the amounts
of friction needed to keep Perky from
sliding off.