Upon arrival at the star Alpha Centauri, which is 4 light years away, an astronaut sends a radio message back to Earth. The message is received 9 years after the astronaut departed Earth. How fast did the astronaut travel

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.