1) Suppose that by stirring 921 g of water you are able to increase its temperature from 19.0° C to 21.0° C. Find the increase in the water's entropy.

_______ J/K

2) A certain automobile engine is performing work at the rate of 31200 W (42 hp) with an efficiency of 24%. At what rate is heat being expelled by the engine?

_______ W

3) A car of mass 1.04 multiply.gif 103 kg is initially moving on a level road at a speed of 15.0 m/s. Compute the increase in temperature of the brakes, assuming that all the mechanical energy ends up as internal energy in the brake system. Assume a total heat capacity of 10,000 J/C°.

_______ deg C

4) The exterior walls of a house have a total area of 196 m2 and are at 11.1°C and the surrounding air is at 6.5° C. Find the rate of convective cooling of the walls, assuming a convection coefficient of 3.2 W/(m2 · C°).

_______ W

5) (a) How much heat is required to raise by 15.90°C the temperature of 1.8 kg of water.

________ cal

(b) How much heat is required to raise by 15.90°C the temperature of 1.8 kg of iron.

________ cal