An ideal otto cycle has a compression ratio of 8. at the beginning of the compression process, air is at 95 kpa and 27 c, and 750 kj/kg of heat is transferred to the air during the constant-volume heat-addition process. taking into account the variation of specific heats with temperature, determine
(a) the pressure and temperature at the end of the heataddition process
(b) the net work output
(c) the thermal efficiency
(d) the mean effective pressure for the cycle.
approximate answers:
(a) 4000 kpa 1500 k
(b) 400 kj/kg
(c) 50 percent
(d) 500 kpa.

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Aflywheel accelerates for 5 seconds at 2 rad/s2 from a speed of 20 rpm. determine the total number of revolutions of the flywheel during the period of its acceleration. a.5.65 b.8.43 c. 723 d.6.86

Ariver flows from north to south at 8 km/h. a boat is to cross this river from west to east at a speed of 20 km/h (speed of the boat with respect to the earth/ground). at what angle (in degrees) must the boat be pointed upstream such that it will proceed directly across the river (hint: find the speed of the boat with respect to water/river)? a 288 b. 21.8 c. 326 d. 30.2