These four photos show features of earth that change with time, some fast and some slow. which of these features could not exist if earth did not have a magnetic field?

The dissociation energy of a molecule is the energy required tobreak apart the molecule into its separate atoms. the dissociationenergy for a particular molecule is 5.48 x 10-18 j. suppose that this energy is provided by a single photon. determinethe (a) wavelength and (b) frequency of the photon

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

Un jugador de beisbol batea un foul recto en el aire. la pelota deja el bate con una rapidez de 120 km/h. en ausencia de resistencia del aire. ? cual sera la rapidez de la pelota cuando la atrape el catcher