Physics
posted by Tina .
I need a complete list all the doppler effect equations for a beginner physics class. Here is a sample questions so you know the level
Question: Two trains on separate tracks move toward one another. Train #1 has a speed of 130 km/hr and train #2 a speed of 90km/hr. Train 2 blows its horn, emitting a frequency of 500 Hz. What frequency is heard by the engineer on train #1?
If you also want to answer/explain the question given that would be helpful.
Mostly though I need a complete list of equations for this level of doppler effect problems. Thanks!

In your question, you have a moving source, and a moving observer (receiver). See this link, and the formula in the "general" section.
http://en.wikipedia.org/wiki/Doppler_effect 
Consider an antenna transmitting at 900 MHz. The receiver is traveling at a speed of 40 km/h. Calculate its Doppler shift.