<P> where K is kinetic energy, m is mass, and v is velocity . Because the mass of a roller coaster car remains constant, if the speed is increased, the kinetic energy must also increase . This means that the kinetic energy for the roller coaster system is greatest at the bottom of the largest downhill slope on the track, typically at the bottom of the lift hill . When the train begins to climb the next hill on the track, the train's kinetic energy is converted back into potential energy, decreasing the train's velocity . This process of converting kinetic energy to potential energy and back to kinetic energy continues with each hill . The energy is never destroyed, but is lost to friction between the car and track . Brakes bring the ride to a complete stop . </P> <P> When going around a roller coaster's vertical loop, the inertia that produces a thrilling acceleration force also keeps passengers in their seats . As the car approaches a loop, the direction of a passenger's inertial velocity points straight ahead at the same angle as the track leading up to the loop . As the car enters the loop, the track guides the car up, moving the passenger up as well . This change in direction creates a feeling of extra gravity as the passenger is pushed down into the seat . </P> <P> At the top of the loop, the force of the car's acceleration pushes the passenger off the seat toward the center of the loop, while inertia pushes the passenger back into the seat . Gravity and acceleration forces push the passenger in opposite directions with nearly equal force, creating a sensation of weightlessness . </P> <P> At the bottom of the loop, gravity and the change in direction of the passenger's inertia from a downward vertical direction to one that is horizontal push the passenger into the seat, causing the passenger to once again feel very heavy . Most roller coasters require passengers to wear a safety harness, but the forces exerted by most loop - the - loop coasters would keep passengers from falling out . </P>

Which area of technology might be associated with this item roller coaster