Final answer:
At the top of a rollercoaster hill, one feels lighter due to downward acceleration reducing the normal force, while at the bottom, one feels heavier because of the increased normal force from deceleration. This is analogous to elevator rides where your apparent weight changes with ascending or descending motion and becomes zero in free fall.
Step-by-step explanation:
When you are at the top of a hill on a rollercoaster, you typically feel lighter due to the effects of the downward acceleration which reduces the normal force acting upon you. This makes your apparent weight less than your actual weight. Conversely, at the bottom of the hill, you often feel heavier because the rollercoaster is decelerating (it is changing direction to go up), and the normal force is greater than the gravitational force, making your apparent weight more than your actual weight.
Similarly, imagine being in an elevator. When the elevator starts ascending, the scale would show a value greater than your weight at rest, because the elevator acceleration adds to the gravitational pull. If the elevator ascends at a constant speed, there is no acceleration and thus the scale shows your actual weight. However, in a scenario where the cable snaps and you are in free fall, the scale would show zero because there would be no normal force acting on you—one feels weightless in this situation.
So, in both scenarios of being in an elevator and on a rollercoaster, your apparent weight changes depending on whether the system is accelerating upwards or downwards.