Answer:
a. 20 seconds
b. 160 seconds
Step-by-step explanation:
a. Frequency is given by
, where
is the period in seconds. Rearranging, we get
. Given that frequency is 0.05 Hz, we have:

b. Since we just found that it takes 20 seconds to complete one rotation (period), it will take
to complete 8 rotations.