Heated air at 1 atm and 25°c is to be transported in a 250 m long circular duct at a rate of 0.45 m/s. if the head loss in the pipe is not to exceed 20m, determine the minimum diameter of the duct.

Apiston-cylinder with a volume of 0.25 m3 holds 1 kg of air (r 0.287 k/kgk) at a temperature of 100 c. heat transfer to the cylinder causes an isothermal expansion of the piston until the volume triples. how much heat is added to the piston-cylinder?

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

The higher the astm grain size number, the finer the gran is. a)-true b)-false