Question

read the text about an object in motion.
dr. howard teaches astronomy. she used to keep a model of mars on the edge of her desk, but one day she decided to hang it up so that her students could see it better. she used a string to tie the model to a hook in the ceiling. a few days later, the string came loose and the model fell to the ground.
when was the most gravitational potential energy stored between the model and earth? assume that the models mass did not change.
when the model was on the edge of dr. howards desk
when the model was hanging from the hook
when the model was about to hit the ground

Explanation:

Gravitational potential energy \( U = mgh \), where \( m \) is mass, \( g \) is acceleration due to gravity, and \( h \) is height. When the model was on the edge of the desk, it had a certain height \( h_1 \) relative to the ground. When hanging from the hook, its height \( h_2 \) (relative to the ground) increased (assuming the hook is above the desk level). When it was about to hit the ground, \( h = 0 \). Since \( U = mgh \) and \( m \) is constant (mass did not change), the gravitational potential energy is highest when the height \( h \) is highest.

Answer:

When the model was hanging from the hook.