Power
2 marks · NormalExplain why, as a rollercoaster descends from the highest point to the lowest, its gravitational potential energy decreases while its kinetic energy increases.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
As the rollercoaster descends, it loses height and so loses gravitational potential energy, which is converted into kinetic energy as its speed increases. The total energy is conserved (ignoring friction).
Also accept: The loss in gravitational potential energy is transferred to kinetic energy so the rollercoaster speeds up; Energy is converted from GPE to KE as the car falls
Common mistakes: Saying energy is lost; Ignoring energy conservation
Show mark scheme and worked solution
Marking points
B1 · 1 mark · States GPE decreases because object loses height
B2 · 1 mark · States GPE is converted to KE as speed increases/energy is conserved
Worked solution
As the rollercoaster descends, it loses gravitational potential energy because its height decreases.
This energy is transferred to kinetic energy, so its speed increases. Total energy is conserved.