A66.5-kg hiker starts at an elevation of 1270 m and climbs to the top of a peak 2660 m high.
(a) what is the hiker? s change in potential energy?
(b) what is the minimum work required of the hiker?
(c) can the actual work done be greater than this? explain.

12 drag each label to the correct category. decide whether each statement describes mass or weight. measured in newtons measured in kilograms does not change when gravity changes === a gravitational force changes when gravity changes the amount of matter in something mass weight

Under conditions for which the same room temperature is maintained by a heating or cooling system, it is not uncommon for a person to feel chilled in the winter but comfortable in the summer. provide a plausible explanation for this situation (with supporting calculations) by considering a room whose air temperature is maintained at 20â°c throughout the year, while the walls of the room are nominally at 27â°c and 14â°c in the summer and winter, respectively. the exposed surface of a person in the room may be assumed to be at a temperature of 32â°c throughout the year and to have an emissivity of 0.90. the coefficient associated with heat transfer by natural convection between the person and the room air is approximately 2 w/m2 â‹…â‹… k. what is the ratio of the thermal resistance due to convection to the thermal resistance due to radiation in the summer? what is the ratio of thermal resistances in the winter

If a spring has a k value of 100 newtons per meter and it is stretched 0.50 meters, what is the restoring force of the spring?