Nhà nước mang bản chất giai cấp có nghĩa là nhà nước chỉ thuộc về một giai cấp hoặc một liên minh giai cấp nhất định trong xã hội. Nhận định này đúng hay sai?

Water at the rate of 1 kg/s is forced through a tube with a 2.5 cm inner diameter. the inlet water temperature is 15°c, and the outlet water temperature is 50°c. the tube wall temperature is 14°c higher than the local water temperature all along the length of the tube. what is the length of the tube?

Define thermoplastic polymers and thermosetting polymers in terms of their structures, and (ii) describe briefly a process suitable for the production of products from each type of polymer.

Steel balls 12 mm in diameter are annealed by heating to 1150 k and then slowly cooled to 400 k in an air att 325 k and h -20 w/m2 k. assume the properties of the steel to be k- 40 w/m k,p 7800 kg/m3, and cp 600 j/kg k. a. determine whether lumped system method can be used to analyze this problem and if so why" b. determine the time required for the cooling process. c. determine the total amount of heat lost from each ball to the ambient air