At the instant u = 60, the boy’s center of mass G is momentarily at rest. Determine his speed and the tension in each of the two supporting cords of the swing when u = 90. The boy has a weight of 60 lb. Neglect his size and the mass of the seat and cords.

An ice-making machine inside a refrigerator operates in a carnot cycle. it takes heat from liquid water at 0.0 degrees celsius and rejects heat to a room at a temperature of 19.2 degrees celsius. suppose that liquid water with a mass of 76.3kg at 0.0 degrees celsius is converted to ice at the same temperature. take the heat of fusion for water to be l_f = 3.34*10^5 j/kg.how much energy e must be supplied to the device? express your answer in joules.