# Homework Help: Speed of Sound Problem

1. Feb 14, 2008

### astros10

1. The problem statement, all variables and given/known data
The effective spring stiffness corresponding to the interatomic force for aluminum and lead. Let's assume for the moment that, very roughly, other atoms have similar values as Pb and Al. Pb has a velocity of 1200 m/s and Al has a velocity of 5000 m/s

(a) What is the (very) approximate frequency f for the oscillation ("vibration") of H2, a hydrogen molecule containing two hydrogen atoms? Remember that frequency is defined as the number of complete cycles per second or "hertz": f = 1/T. There is no one correct answer, since we're just trying to calculate the frequency approximately. However, just because we're looking for an approximate result doesn't mean that all answers are correct! Calculations that are wildly in disagreement with what physics would predict for this situation will be counted wrong.

(b) What is the (very) approximate frequency f for the vibration of O2, an oxygen molecule containing two oxygen atoms?

(c) What is the approximate vibration frequency f of D2, a molecule both of whose atoms are deuterium atoms (that is, each nucleus has one proton and one neutron)?

2. Relevant equations
w=sqrt(Ks/M)
f=w/(2pi)

3. The attempt at a solution
I can't figure out how to calculate Ks or M given just the velocities of the other elements.