How does a guitar string make a sound wave? a. striking the string compresses the air around it to create a sound wave. b. the vibrating string alternately compresses and rarefies the air to make sound. c. the string strikes the wood of the guitar, which vibrates to make the sound. d. the string moves air through the hole in the guitar to create sound. **i am not sure : (

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)