Last summer, it took a group of friends about two hours to hike up a small peak in the Rocky Mountains. This year, they are doing the same hike, but this time, they will be carrying 40-pound backpacks. Why should they expect it to take longer this time?
a. Its cooler this summer
B. Newtons second law of motion
C. You're not as in shape as last summer
D. Newtons third law of motion