An overflow ogee crest for a spillway is to discharge 20,000 cfs. the upstream face of the crest is sloped 1: 1 and a bridge is to span the crest. flow over the spillway is to be controlled by a series of tainter gates. bridge piers 18-in wide (pier contraction kp = 0.05) with rounded noses are to be provided to support the gates. the bridge spans (center to center of piers) are not to exceed 30 ft. the maximum expected head he = 10 ft. neglect velocity of approach head. the distance from the spillway crest to the reservoir bottom p = 18 ft. the abutment coefficient ka = 0.10. assume that your design head is equal to the maximum expected head. determine: (ans: l’ = 169.4-ft,) (a) the crest length required (b) the number of tainter gates to be used (c) the width of each gate

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?