In a theme park, passengers in a car are initially at rest at the top of the track. The car then travels down and round a circular loop in the track.
What form(s) of energy is possessed by the car and passengers at points [tex]$X$[/tex] and Y?
KE = kinetic energy; GPE = gravitational potential energy
| | X | Y |
|---|---|---|
| A | GPE only | KE only |
| B | GPE only | KE and GPE |
| C | KE only | GPE only |
| D | KE only | KE and GPE |
Answer (2)
At point X, the car possesses gravitational potential energy only.
At point Y, the car possesses both kinetic and gravitational potential energy.
Therefore, option B is the correct answer.
The correct answer is B .
Explanation
Energy at Point X At point X, the car is at its highest point and momentarily at rest. This means it has maximum gravitational potential energy (GPE) and zero kinetic energy (KE).
Energy at Point Y At point Y, the car has moved downwards and is in motion. This means it has kinetic energy (KE). Since point Y is not at the lowest possible point, it also retains some gravitational potential energy (GPE).
Conclusion Based on the above analysis:
At point X: GPE only
At point Y: KE and GPE Therefore, the correct option is B.
Examples
Understanding energy transformations is crucial in designing roller coasters. At the highest point, the car has maximum potential energy, which converts to kinetic energy as it descends. Engineers use these principles to ensure the ride is thrilling but safe, controlling the speed and forces experienced by passengers. For example, calculating the potential energy at the start helps determine the necessary track height and loop sizes to maintain sufficient speed throughout the ride, ensuring the car completes the loop without stopping.
At point X, the car has gravitational potential energy (GPE) only, and at point Y, it has both kinetic energy (KE) and gravitational potential energy (GPE). Thus, the correct multiple-choice option is B. This reflects the conversion of energy as the car moves along the track.
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