A person, with a mass of 50.0 kg, stands on a weighing scale in a lift which is moving upwards with a uniform acceleration of 5.0 m/s
2
. What would be the reading on the
scale?
(A) 490 N (B) 250 N (C) 740 N (D) 240 N

An air standard cycle with variable specific heats is executed in a closed system and is composed of the following four processes. 1-2 isentropic compression 100 kpa and 22°c to 600 kpa 2-3 v=constant heat addition to 1500 k 3-4 isentropic expansion to 100 kpa 4-1 p=constant heat rejection to initial state (a) show the cycle on p-v and t-s s (b) calculate the net work output per unit mass (409 kj/kg) (c) determine the thermal efficiency (47.9%)