Question

read the text about a person in motion.
lena performs stunts on movie sets. for one stunt, lena started on the first story of a building. she ran up a staircase until she reached the third story. she dashed to a balcony, where she slid down a rope into an open window on the second story of another building. she landed safely on the floor inside the open window.
when was the least gravitational potential energy stored between lena and earth? assume that lenas mass did not change.
when she was at the bottom of the staircase
when she was standing on the balcony
when she was on the floor inside the window

Explanation:

Step1: Recall gravitational potential energy formula

Gravitational potential energy \(U = mgh\), where \(m\) is mass, \(g\) is acceleration due to gravity, and \(h\) is height.

Step2: Analyze each situation

• When at the bottom of the staircase: \(h\) is minimum (\(h\approx0\)), so \(U\) is minimum.
• When standing on the balcony: \(h\) is relatively large.
• When on the floor inside the window: \(h\) is relatively large.

Answer:

When she was at the bottom of the staircase.