Carbon steel (aisi 1010) shafts of 0.1-m diameter are heat treated in a gas-fired furnace whose gases are at 1200 k and provide a convection coefficient of latex: 100\: \frac{w}{m^2.k}100 w m 2 . k. if the shafts enter the furnace at 300 k, how long (in seconds) must they remain in the furnace to achieve a center-line temperature of 800 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