When they are far apart, the momentum of a proton is <3.9 × 10-21, 0, 0> kg·m/s as it approaches another proton that is initially at rest. The two protons repel each other electrically, without coming close enough to touch. When they are once again far apart, one of the protons now has momentum <1.0 × 10-21, 4.6 × 10-21, 0> kg·m/s. At that instant, what is the momentum of the other proton? (Express your answer in vector form.)

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%)