Atest is conducted to determine the overall heat transfer coefficient in a shell-and-tube oil-to-water heat exchanger that has 24 tubes of internal diameter 1.2 cm and length 2 m in a single shell. cold water (cp = 4180 j/kg·k) enters the tubes at 20°c at a rate of 3 kg/s and leaves at 55°c. oil (cp = 2150 j/kg·k) flows through the shell and is cooled from 120°c to 45°c. determine the overall heat transfer coefficient ui of this heat exchanger based on the inner surface area of the tubes. 8.31 kw/m2·k

An engine, weighing 3000 n, is supported on a pedestal mount. it has been observed that the engine induces vibration into the surrounding area through its pedestal at the maximum operating speed. determine the stiffness of the dynamic vibration absorber spring in (n/m) that will reduce the vibration when mounted on the pedestal. the magnitude of the exciting force is 250 n, and the amplitude of motion of the auxiliary mass is to be limited to 2 mm note: in this question type-in right numbers, no decimals, no fractions, no unit. approximate to right number if needed