Final answer:
Roller coaster designers focus on physical movement, which involves the real motion of roller coaster cars and the experience of forces such as centripetal acceleration and gravity on the passengers.
Step-by-step explanation:
Roller coaster designers primarily focus on physical movement when creating their rides. This type of movement pertains to the real motion of the roller coaster cars and their passengers through space. Designers use elements such as teardrop-shaped loops and curved paths to ensure that the forces acting on the riders, such as centripetal acceleration and gravity, contribute to a thrilling yet safe experience. Specifically, teardrop-shaped loops are engineered to manage the radius of curvature, allowing for a gradual increase and decrease of centripetal acceleration, which avoids the jolting changes that a circular loop would cause.
The correct answer to the given question is (c) Physical. This encompasses not only the direction and shape delineated by the track but also the forces experienced by riders as they navigate through the loops and turns of the roller coaster.
It is important to note that roller coaster designers must carefully calculate the speeds and forces involved to ensure that, for instance, at the top of a loop the force exerted by the coaster car on the passenger is safe and appropriate for the conditions.