An oil refinery produces oil at a variable rate given by the following equation, where t is measured in days and q is measure in barrels. upper q prime left parenthesis t right start 3 by 2 matrix 1st row 1st column 600 2nd column if 0 less than or equals t less than 30 2nd row 1st column 2500 minus 50 t 2nd column if 30 less than or equals t less than 40 3rd row 1st column 400 2nd column if t greater than or equals 40 endmatrix a. how many barrels are produced in the first 35 days? b. how many barrels are produced in the first 50 days? c. without using calculus, determine the number of barrels produced over the interval [70,90].

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 freezing and boiling point of a substance changes as the air pressure around it changes. for example, at a lower air pressure (higher altitude) it is easier for water molecules to escape from liquid into the air. in a high altitude city such as denver, colorado compared to a sea-level city such as houston, texas, water

Ahorizontal force of 400.0 n is required to pull a 1760 n truck across the floor at a constant speed. find the coefficient of sliding friction.