car·ou·sel (plural car·ou·sels)noun
amusement park ride: an amusement
park or fairground ride with a rotating
circular platform fitted with seats that
are
usually shaped like animals such as
horses
and move up and down to music.
The carousel originated in Europe, but reached its greatest fame in America in the
1900's. The first carousels featured gondolas, carts, menagerie animals, and
horses. The French developed many variations of the carousel. In one variation,
the riders tried to spear gold rings with lances while the carousel rotated at full
speed. This undoubtedly led to the phrase, "catching the brass ring" on later
carousels.

In the mid 16th century, grand tournaments were held in France. Saddle makers,
tailors, jewelers, and wig makers created extravagant costumes for both horse and
rider for these occasions. Inspiration for later carousel carvers apparently
originated from these events.

During the late 1900's, many skilled European carvers immigrated to the United
States to produce carousels. The carvings of these immigrants were a great
improvement over the first efforts of unskilled carvers. Usually the side of the
carousel horse facing the audience, the "Romance" side, was adorned with carved
decorations, while the inner side received little attention.
The golden age of carousels only lasted 25 years, but still brings back wonderful
childhood memories today. Even though 7,000 carousels were created years ago,
only 300 remain in existence today.

Carousels are not considered "thrill machines" by any stretch of the imagination. Still,
carousels are as reliant on the laws of motion as their more exciting cousins, the roller
coasters. It's theoretically possible that, allowed to spin out of control, a carousel could
gain enough speed so that the riders would be thrown off. Thankfully, runaway
carousels are not the least bit common.

Are some horses moving faster than others?
With all of its beauty and seeming simplicity, the carousel is a delicate balance of motion
and forces. All of the horses move through one complete circle in the same amount of
time. The horses on the outside of the carousel have to cover more distance than the
inside horses in this of time. This means the horses on the outside have a faster linear
speed than those at the hub.

What if they're galloping?
On some carousels, the horses go up and down in a galloping motion simulating what it
might be like to ride a real horse. For these carousels, the ride designer had to
approach the problem of movement around the central axis differently. In a normal
carousel, each horse maintains a constant acceleration, radius, and tangential speed
(speed tangent to the circular path of the carousel). If you add a gallop to some of the
horses, you must consider the forces needed to change that horse's position upward or
downward as it goes around the track. In designing with these forces in mind, you also
need to take into account the mass of the horse and its rider.
http://www.learner.org/exhibits/parkphysics/carousel.html
Facts and History of Carousels and Carousel Horses--   
                                  American and European