Which statement best describes the effect of scientific advances on society? a. they always have a positive impact on society. b. they are inspired by the needs of society. c. they do not affect society beyond the community level. d. they always increase the cost of produce and technology.

In a system, when potential energy decreases, then entropy also decreases. true false

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.