calculate the average force (in N) a 70.0 kg sprinter exerts backward on the track to accelerate from 2.00 to 8.50 m/s in a distance of 25.0 m, if he encounters a headwind that exerts an average force of 30.0 N against him.

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 air during the constant-volume heat-addition process. assuming constant specific heats at room temperature, determine (a) the pressure and temperature at the end of the heat-addition process, (b) the net work output, (c) the thermal efficiency, and (d) the mean effective pressure for the cycle. (4390 kpa, 1730 k; 423 kj/kg; 56.4%; 534 kpa)