Final answer:
To determine the normal force at the bottom of a roller coaster loop, the speed needs to be calculated using the conservation of energy, and then the centripetal force requirement can be used to find the normal force. Without the actual loop height 'h', a numerical answer cannot be provided.
Step-by-step explanation:
To calculate the normal force exerted by the track at the bottom of a loop-the-loop, you need to consider the forces acting on the roller coaster at that point. This scenario involves circular motion, and thus we have to use the concept of centripetal force; which in this case is provided by the normal force and the component of gravitational force acting towards the center of the loop. The roller coaster has a mass of 850 kg, the release height is 2.4 h (where h is the height of the loop which is not given in the question), and assuming no frictional forces are at play, we could use conservation of energy to find the speed at the bottom of the loop and then apply Newton's second law to find the normal force. However, since the actual height of the loop 'h' is not specified, a numerical answer cannot be computed. The process would typically include equating the potential energy at the release height to the kinetic energy at the bottom plus the potential energy at the bottom of the loop, calculating the speed, and subsequently using this speed to calculate the centripetal force required for circular motion at the bottom of the loop, which would be the sum of the weight of the roller coaster and the normal force exerted by the track.