Figure 10.29 in your textbook is an energy bar chart for a mountain climber pulling a bag of supplies up a slope. Suppose, instead, she uses the rope to lower the bag down the slope. Which of the bars of the chart will be negative? Select all that apply,

a.) Ki

b.) Kf

c.) Ui

d.) Uf

e.) Wext

f.) ΔEth

Please explain why, I have an exam coming up on this and want to understand.