A construction worker drives to his work 43 km away at an average speed of 62 km/h. Before he gets out of his car he realizes he forgot his hammer at home and drives back at 79 km/h. Assuming his time parked at work was insignificant, what was his average speed overall in km/h?

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.

What is the change in internal energy if 20 j of heat is released from a system and the system does 50 j of work on the surroundings? a. -70 j b. 30 j c. -30 j d. 70 j

Write a brief essay describing the minimum requirements for any electric circuit. within your essay,