The steady, surface temperature of a lake changes from point to point and is given to you as a function T(x, y) (assume the surface of the lake is in the (x, y) plane). If you attach a thermometer to a boat and take a path across the lake surface defined by the trajectory (x(t), y(t)) = (bi(t), b2(t)), find an expression for the rate of change of the thermometer temperature in terms of the lake temperature.

An ideal otto cycle with air as the working fluid has a compression ratio of 8. the minimum and maximum temperatures in the cycle are 300 k and 1340 k. use constant specific heats at room temperature to determine (a) the amount of heat transferred to the air during the heat- addition kj/kg, (b) the thermal efficiency, and (c) the thermal efficiency of a carnot cycle ope limits. process, in rating between the same temperature