The power in a lightbulb is given by the equation p = r, where i is the current flowing through the lightbulb and r is the resistance of the lightbulb. what is the current in a circuit that has a resistance of 30.0 (look at image attached for symbol) and a power of 55.0 w? ? a. 1.83 a b. 0.740 a c. 1.35 a d. 0.550 a

An astronomer at the equator measures the doppler shift of sunlight at sunset. from this, she calculates that earth’s tangential velocity at the equator is 465 m/s. the centripetal acceleration at the equator is 3.41  10 2 m/s 2 . use this data to calculate earth’s radius.

Spend time observing or thinking about events that involve matter and energy. which events can you explain? which events can’t you explain?

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