A hiker of mass climbs from the base of a mountain at an elevation of above sea level…
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Work Energy and Power · Work Energy and Power
Problem
A hiker of mass 70kg climbs from the base of a mountain at an elevation of 1200m above sea level to a cabin located at 1800m. Assume the magnitude of Earth’s near-surface gravitational field is g=9.8ms−2 and may be taken as constant over the entire climb. Air resistance and other non-conservative forces may be neglected. Unless otherwise indicated, take the zero of gravitational potential energy at the mountain’s base.
(a) Calculate the gravitational potential energy of the hiker–Earth system when the hiker reaches the cabin.
(b) Suppose instead that the zero of gravitational potential energy is chosen at the cabin’s elevation. Determine the gravitational potential energy of the hiker–Earth system when the hiker is standing at the mountain’s base under this new convention.
(c) Explain how the numerical results from parts (a) and (b) illustrate the arbitrariness of the reference level for potential energy and why the physical predictions for the hiker’s effort remain unaffected by that choice.