jlowe22

On 8/21/2023 at 7:29 PM, iNow said:

Don't be too hard on yourself. NASA made a remarkably similar mistake a little while back: https://www.wired.com/2010/11/1110mars-climate-observer-report/

In my defense the book uses km/hr, but yes I certainly should have caught the problem before spending so much time on it.

5 hours ago, Genady said:

You get the book answer if you use 100 mph instead of 100 km/hour.

Of course.  I knew something silly was going on, I could get the book answer using 44.6 m/s but I didn't make the connection to mph.

Thanks guys.

1 hour ago, Genady said:

I'm getting about 2000.

I get ~ 1951 every time I try.

The problem is 5-5 part d.  As worded is:

"One radar gun used by the Massachusetts Highway Patrol operates at a frequency of 10.525 X 10⁹ cycles/second. By how many cycles/second is the reflected beam shifted in frequency when reflected from a car approaching at 100 kilometers/ hour?"

The book gives the answer 3136, and I can't for the life of me get this answer.  I've done this multiple ways and get the same wrong answer every time.  Doing similar problems elsewhere I'm getting right answers, so I can only conclude that either I'm overlooking something really, really silly, or there's a typo somewhere in the book.  If someone can confirm that 3136 is indeed the right answer, I'll go on trying to figure out where I screwed up.

The link to the full problem is here:

https://phys.libretexts.org/Bookshelves/Relativity/Spacetime_Physics_(Taylor_and_Wheeler)/05%3A_Trekking_through_Spacetime/5.E%3A_Trekking_through_Spacetime_(Exercises)

It would mean he punches you before he punches you.

On 3/17/2018 at 9:59 PM, Moreno said:

Despite the presence of an iron core, Ganymede's magnetosphere remains enigmatic.

An unsolved enigma.

There are plenty of unsolved enigmas in life, I don't understand your point.  

Or is this a thread where we get to post random unsolved enigmas?