How efficient is a pulley system if it enables you to lift a 700.0 Newton engine 0.550
meters if you exerted 35.7 Newtons of force while pulling 11.43 meters of rope?

You are a sales representative for a company that makes a new alternate fuel for vehicles. you have prepared a presentation for the environmental engineers to sell your new product. what question do you expect the audience to ask regarding whether the new fuel will cause less damage to the environment? a. do we have to change any parts of the vehicle to use this alternate fuel? b. will the vehicles get better fuel mileage with the alternate fuel? c. how much greenhouse gas does your fuel produce compared with current fuel sources? d. is the alternate fuel more expensive than fossil fuel?

Sobre transformações cíclicas, são feitas algumas afirmações, determine quais estão corretas. i – a variação de energia interna em uma transformação cíclica é nula; ii – o trabalho, em uma transformação cíclica, é sempre positivo; iii – ao completar um ciclo, o gás tem a mesma temperatura com a qual começou a transformação; iv – uma transformação cíclica é, obrigatoriamente, composta de transformações conhecidas, como adiabática, isocórica, etc: a) i e iii b) i e ii c) ii e iii d) i e iv e) iii e iv

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)