From my research and understanding of roller coasters, their speed is mainly impacted by the force of gravity and it works on the basis of potential energy build up into kinetic energy. Therefore, my question surrounds the idea of safe speeds on coasters. Because a roller coaster car is only impacted by gravity, what is a safe speed and how might it be calculated? Is there an equation for this? I have researched online and have yet to find any information regarding this topic. Thank you in advance!