Physics LO

1. STANDING WAVES

2.  Definition:
 A standing wave can be described as the following equation:
Where A(x) can be defined as

3.  A(x) is a sine function, thus certain points on the function would
have zero amplitude.
 Points where A(x)=0 are called nodes
 Points that move with the maximum possible amplitude are call
antinodes

4. HOW TO CALCULATE LOCATION OF
NODES AND ANTINODES
Location of nodes: Location of antinodes

5. QUESTION!
 Identify nodes and antinodes from the given graph:

6. ANSWER!
Node: 0, 180, 360
Antinode: 90, 270

7. STANDING WAVES ON STRINGS
The equation:

8. The allowed frequencies
are called harmonics or
resonant frequencies and
is represented by the
equation:

9. QUESTION!
A violin string is 0.52m long and has a linear mass
density of 3.58 x 10^(-4) kg/m. The tension in the
string is kept at 100.0N.
a) What is the wave speed in the string?
b) By what amount should the tension be changed
to decrease the fundamental frequency by 10
HZ?

10. ANSWER!
 A)
V= 589m/s
B)
(Hint: first find the original fundamental frequency and then
calculate)
Amount of tension needs to be changed: 3.5N

11. THANK YOU FOR WATCHING!