Question

Help me? umm okay then. Explain the Doppler effect?

Answer 1

lol.. you shoudl read your text book for that
and then when u don't understand something.. ask for doubts here :P

Answer 2

lol i wish i had a text book, im homeschooled

Answer 3

the change in frequency of a wave (or other periodic event) for an observer moving relative to its source. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach, identical at the instant of passing by, and lower during the recession.