Final answer:
The total potential energy of the ball just as Yoselin releases it remains 5 joules, the same as when she holds it. As the ball falls, its potential energy is converted to kinetic energy, but the sum of both types of energy remains constant assuming a closed system without energy loss.
Step-by-step explanation:
When Yoselin holds the ball and it has 5 joules of potential energy, this is the gravitational potential energy of the ball due to its position above the ground. If Yoselin releases the ball, the total potential energy of the system is momentarily still 5 joules just as she lets go, assuming no energy has been added or removed from the system. As the ball falls, this potential energy is converted into kinetic energy, but the total mechanical energy of the system (the sum of potential and kinetic energy) remains constant at 5 joules, ignoring air resistance and assuming a closed system.
To calculate the gravitational potential energy at any point during the fall, the equation PE = mgh (mass times gravity times height) is used. However, when the ball is about to hit the ground, its height above the ground is zero, which means its gravitational potential energy is 0 joules at that moment, with all of its initial potential energy having been converted into kinetic energy.