A roller-coaster car moves through four consecutive segments:
1. a long, frictional descent from the top of the first hill to the bottom,
2. a vertical loop made of the same track material,
3. an uphill climb to a shorter second hill where the track material is unchanged, and
4. a short straight section where brakes press against the wheels with a much larger constant force than the track friction.
Assume the mass of the car is constant and air resistance is negligible. Which segment results in the greatest decrease in the car’s mechanical energy?
a) the passage through the vertical loop
b) the straight section where the brakes are applied
c) the descent from the first hill to the bottom
d) the climb to the top of the second hill