Homework Help: Car approaches Radio station

1. May 13, 2010

Planter

1. The problem statement, all variables and given/known data

The car is approaching a radio station at 25m/s. Broadcast frequency is 74.5 MHz.

What change in frequency does the driver observe.

2. Relevant equations

Doppler effect on EM waves

Fo = Fs (1 (+/-) u/c)

u = speed of observer

c = speed of light

3. The attempt at a solution

Got it ,, answer is 62.08 Hz

Last edited: May 13, 2010
2. May 13, 2010

Staff: Mentor

Definitely the Doppler Effect. Keep on reading a bit, and you'll see it addressed. Show us what you get for an answer!

3. May 13, 2010

Planter

Are you sure? Because doppler effect was taught "last semester" in part one of this class. Which is why I am weary of using it... It's not sound frequency i don't think.

4. May 13, 2010

Staff: Mentor

Well, what is the Doppler Effect (define it in your own words -- don't look up the definition yet)?

And, what would be different if the source was a stationary whistle, instead of a radio station? What would be the same?

5. May 13, 2010

Planter

The frequency is in MHz.. Would a doppler effect question be in MHz??

6. May 13, 2010

Planter

Ok, I got it.. Found it,, haha Doppler effect on EM waves, Chapter 21.13.... Thank god for PDF books. I was only searching in chapters 26+ because all the questions prior to this one was pertaining.

7. May 13, 2010

Staff: Mentor

Just to complete this learning module, please do a quick search on the Hubble Red Shift (at wikipedia or elsewhere). Do you see the theme?