Av-belt is to be used to transmit 10 kw from a 250 mm diameter pulley running at 720 rpm to a 750 mm diameter driven pulley. the centre-distance of the pulleys is 600 mm. the half-groove angle of the pulley is β=18° and the mass of the belt is 0.25 kg/m 1. determine the operating tensions in the belt, assuming a coefficient of friction of u 0.3 and the initial tension in the belt is just enough to prevent slipping 2. determine this initial tension and explain how this may be achieved (include sketches as appropriate)

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?