A hollow steel tube has a diameter of 300 mm, wall thickness of 20 mm and a length of 500 mm. A slot 20 mm wide is machined through the wall thickness and along the whole length of the
tube. The tube is positioned on a rigid horizontal surface with the slot at one extreme of a
horizontal diameter. A force W is then applied on the upper surface along the vertical diameter
and uniformly along the length of the tube. Calculate the magnitude of this force which is
necessary to just close the slot

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?