When you ride a bicycle at constant speed, nearly all the energy you expend goes into the work you do against the drag force of the air. model a cyclist as having cross-section area 0.43 m2 and, because the human body is not aerodynamically shaped, a drag coefficient of 0.90.
part a) what is the cyclist's power output while riding at a steady 7.3 m/s (16mph)?
part b) metabolic power is the rate at which your body "burns" fuel to power your activities. for many activities, your body is roughly 25% efficient at converting the chemical energy of food into mechanical energy. what is the cyclist's metabolic power while cycling at 7.3 m/s?
part c) the food calorie is equivalent to 4190 j. how many calories does the cyclist burn if he rides over level ground at 7.3 m/s for 1.5h ?

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

The bubbles in a carbonated soft drink are produced when carbonic acid decomposes to form carbon dioxide and water. in a closed system, this equilibrium exists as why does a carbonated soft drink lose carbonation when the container is left open? a.water evaporates, which favors the formation of h2co3. b.pressure decreases, which favors the formation of h2co3. c.the open container warms up, which causes more gas to escape. d.co2is removed, which favors the formation of h2co3.

If you divide a speed in miles per minute by 60, you get the same speed expressed in miles