Pre-Lab: Standing Waves                   Name:

 

In the following problems, refer only the left most loops (as indicated in the lab manual) of a standing wave beginning at the bridge (count this left most node.)

 

1.     (½) What is the correct number of nodes if you count 3 antinodes from the left?

a.     2

b.    3

c.     4

d.    depends on arrangement

 

 
  1. (½) Referring to the previous problem, three antinodes represent how many loops?
    1. 2
    2. 3
    3. 4
    4. depends on the arrangement

 

3.    (1) In today’s lab you may suspend 0.102 N over the pulley at the edge of the table.  If the string has a m value of 2.56 x 10-3 g/cm, what is the velocity of this wave?

a.     40 m/s       (show work; include units)

b.    6.3 m/s

c.     400 m/s

d.    20 m/s

 

 

 

 

4.    (1)  In today’ lab, wavelength (l) is determined for various string tensions.  v = fl ; v = √FT/√μ

            f   l     =   √FT  /  √μ        (Hint:  check data sheet)

 

 

 

         y      =     m       x        +     b      

Re-write the above equation in slope-intercept form (shown above) so that the slope is calculated by, D√FT / Dl.  Also which unknown is determined by this slope _______.

 

5.    (2) Using the following data and the known value of m = 2.56 x 10-3 g/cm, calculate the frequency of the string. (fill in table and show work for slope calc)

a.     50

b.    125

c.     195

d.    40

e.    14

 

 

n

(# of loops)

mass

(grams)

√Tension

(√Newton)

L

(cm)

Wavelength

(m)

1

629

 

 

l1 = 1.321

2

329

 

 

l2 = 1.011

5

91

 

 

l3 = 0.566