# Standing Waves help 30 mins left.

Standing Waves help!!!! 30 mins left.

Hello everyone who's here, so far I've been doin great on waves, but what the heck is standing eave?

Here is a problem that I kinda get, but not completely:

Two strings, with the same mass/length m oscillate with the same frequency f=2.00 Hz. The first string has length L1, tension T1 and vibrates in the fundamental mode (n=1). The second string has length L2, tension T2 and vibrates in the third harmonic (n=3). Assuming L2=2.30 L1:

a) What is the ratio T1/T2?

b) What would be the frequency of the second string if it oscillates in the mode n=1?

what the hell is fundamental mode?
please help, or at least give hints,
thanks a lot

## Answers and Replies

well it's kinda late now, and i got the answers here:

1) 1.70
2) 0.667 Hz

Can anyone tell me how to get them at least so i know how to do them on the test?? (formulas may be)???

Main fomulae:

L= (2n-1)(wavelength)/4

and velocity=(frequency)(wavelength)

where L=length of string

are u saying to find wavelength first?
what about the tension?

OlderDan
Science Advisor
Homework Helper
evgeniy said:
are u saying to find wavelength first?
what about the tension?

The speeds of the waves are equal to sqrt(tension/mass per unit length). Since the masses are the same, ratio of speeds will be the square root of the ratio of tensions.