Aspear of length 8.0 m is thrown with high velocity through the open windows of a room 6.0 m long. (a) how fast must the spear move so that it barely fits in the room when passing through? (b) in the spear’s reference frame, which occurs first: (1) the front of the spear leaving the room or (2) the rear of the spear entering the room? what is the time difference in ns? hint: from (a) these two events occur simultaneously for someone at rest in the room.

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)