Answer:
3 Cycles
Explanation:
Every cycle on a cosine function are marked by the completion of 5 key points when moving along the x-axis:
(5, 0, -5, 0, 5)
This cycle has a frequency of 2, occurring once every second, thus answering our question easily.
When a pendulum is at the midpoint of its oscillation, hanging straight down ...
-- that's the fastest it's going to swing, so its kinetic energy is maximum;
and
-- that's the lowest it's going to get, so its potential energy is minimum.
'c' is your choice.
3. Rubbing Sticks together to create a fire.
5. Gravity.
