Which of these correctly describes the potential and kinetic energy
of the bicycle rider?
J. As the rider moves up the hill, her KE increases and PE decreases.
K. When the rider goes down the hill her PE increases and KE
decreases.
L. At the top of the hill her PE is the greatest, and KE the least.
M. As the rider reaches the bottom of the hill, her KE and PE
decrease.
Q3

Let's analyze each statement to determine which one correctly describes the potential and kinetic energy of the bicycle rider: J. As the rider moves up the hill, her KE increases and PE decreases. - This statement is incorrect. As the rider moves up the hill, she is working against gravity, which means her potential energy (PE) is increasing because she is gaining height. During this time, unless she is pedaling harder to maintain speed, her kinetic energy (KE) would typically decrease since gravity is acting against her motion. K. When the rider goes down the hill her PE increases and KE decreases. - This statement is also incorrect. When the rider goes downhill, she is losing height, so her potential energy (PE) decreases. At the same time, her kinetic energy (KE) increases because gravity is now aiding her motion, causing her to speed up. L. At the top of the hill her PE is the greatest, and KE the least. - This statement is true. At the top of the hill, the rider is at the maximum height relative to the bottom of the hill, which means her gravitational potential energy (PE) is the greatest. As for kinetic energy (KE), if the rider has stopped pedaling and is momentarily at rest before descending, her KE would be the least (at a minimum). If she is moving at the top, her KE may not be the least it could possibly be, but it is likely to be less than it will be when she descends and gains speed. M. As the rider reaches the bottom of the hill, her KE and PE decrease. - This statement is incorrect. When the rider reaches the bottom of the hill, her potential energy (PE) will be at its lowest point because she is at the lowest elevation. However, her kinetic energy (KE) will be at its greatest if she is moving the fastest due to acceleration from the descent. From this analysis, the correct statement is L: "At the top of the hill her PE is the greatest, and KE the least." Assuming we're considering the typical scenario where the rider slows down or momentarily stops at the top, the PE would be maximized due to the height and the KE minimized because of the reduced speed.