Discussion Topic
A system is a group of parts that can be
considered one unit. Storm systems,
ecosystems, and our bodies are natural systems.
Cars and houses are human-made systems.
Choose an example of a system, and analyze
the energy flow through the system. Describe in
detail how energy enters the system, how energy
changes form while in the system, and how
energy leaves the system.

Atrain is traveling at 30.0 m/s relative to the ground in still air. the frequency of the note emitted by the train whistle is 262 hz. the speed of sound in air should be taken as 344 m/s. what frequency (f approach) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first train and approaching it? what frequency (f recede) is heard by a passenger on a train moving at a speed of 18.0 m/s relative to the ground in a direction opposite to the first train and receding from it?