Who says a science day at a theme park had to be just about roller coasters going at great speeds or dropping from great heights. Take time to study the effects of centripetal force on the Carousel.
The centre piece of the Park is the Carousel, housed in a purpose-built domed pavilion. It was built by the Philadelphia Toboggan Co. (PTC) of the USA in 1913 on order for the White City amusement park in Sydney. This park closed in 1918 and the Carousel was later purchased for nearly £15,000 and moved to Luna Park, Melbourne.
On the Carousel we feel as though we are being flung (gently) outwards. We sometimes call this apparent outward force a centrifugal force. Relative to the Carousel that is true enough, but of course we know that it is not an inertial frame of reference and so Newton's laws don't seem to work. In fact all good physics students know that from an inertial frame we see that there is circular acceleration (toward the centre of the Carousel) and so there must be an inward centripetal force – which is provided by the horse we are riding or the post we are holding.
Carousels are not considered "thrill machines" by any stretch of the imagination. Still, carousels are as reliant on the laws of motion as are 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.
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 the same amount of time. This means the horses on the outside have a faster linear speed than those at the hub.
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.
