Air at 20°c and 1 atm flows over a spherical object at 1 m/s. the sphere has a diameter of 10mm and its initial temperature is 134°c. if the density, specific heat, and conductivity of the sphere are 7832 kg/m”, 549 j/kg. k, and 49.2 w/m. k, respectively, calculate the temperature at the center of the sphere after 100 seconds.

An electric kettle is made out of stainless steel, weighs two pounds (when empty) and is equipped with a heating element that consumes 2 kw of electricity. assuming that the water and the kettle are at the same uniform temperature at any moment of time, calculate the shortest possible time to bring 2 quarts of water from room temperature to the onset of boiling

Tom is having a problem with his washing machine. he notices that the machine vibrates violently at a frequency of 1500 rpm due to an unknown rotating unbalance. the machine is mounted on 4 springs each having a stiffness of 10 kn/m. tom wishes to add an undamped vibration absorber attached by a spring under the machine the machine working frequency ranges between 800 rpm to 2000 rpm and its total mass while loaded is assumed to be 80 kg. a) what should be the mass of the absorber added to the machine so that the natural frequency falls outside the working range? b) after a first trial of an absorber using a mass of 35 kg, the amplitude of the oscillation was found to be 10 cm. what is the value of the rotating unbalance? c) using me-3.5 kg.m, find the optimal absorber (by minimizing its mass). what would be the amplitude of the oscillation of the absorber?

Not a characteristic property of ceramic material (a) high temperature stability (b) high mechanical strength (c) low elongation (d) low hardness