Water is forced through a contraction and because of bernoulli’s equation a low pressure is created in the contraction. if the water is at 70oc, and you are at a location of 4000 meters above sea level, what is the minimum absolute and gauge pressure (kpa) that can be produced in the contraction? why is this the minimum pressure?

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.

What is the role of lenses in microscopy?

You hang a book bag on a spring scale and place the bag on a platform scale so that the platform scale reads 23.7n and the spring scale reads 13.8n. what is the magnitude of the force that earth exerts on the bag?