V = velocityL = length of rodFind Frequency of Steel Rod - 1.44m Long

[afcwestwarrior]

Homework Statement

A steel rod of length 1.44 m is clamped at a point 1/4 of its length from one end. The ends of the rod are free to vibrate. If the velocity of longitudianl wave in steel is 5000 m/s, find the frequency of the first three allowed harmonics. Make diagrams to show the three standing waves.

Homework Equations

f (frequency = n V/ 2 L

The Attempt at a Solution

All you have to do is plug in the variable. What I would like to know is how my freinds or classmates found the harmonics.

For frequency one they use 2 harmonics

and for F2 they use 6 harmonics

and for F3 they use 10 harmonics.

How did they figure that out.

n = harmonics

 

[lanedance]

i think you do it by first defining the fundamental frequency,

then using the fact the ends will be open, ie points of maximum oscillation and the clamped point will have zero oscillation

use the short length from clamp to edge to define a requirement for allowable wavelengths