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fruitl00p
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Homework Statement
Two transverse waves traveling on a string combine to a standing wave. The displacements for the traveling waves are Y1(x,t) =0.0160m sin(1.30m^-1x -2.50s^-1t + 0.30) and Y2(x,t) = 0.0160m sin(1.30m^-1x -2.50s^-1t +.070), respectively, where x is position along the string and t is time.
1. Find location of the first antinode for the standing wave at x>0
2. Find the t>0 instance when the displacement for the standing wave vanishes everywhere.
Homework Equations
lambda=2pi/k
f2pi = w
T= 1/f
The Attempt at a Solution
I tried:
y(x,t) = (Asw sinkx)cos wt
with Asw= 2A = 2(0.0160)
k=1.30 m^-1
w= 2.50 s^-1
then lambda= 2pi/k = 2pi/1.30 = 4.83
first node that is x>0 is lambda/2 = 2.416
but looking for first antidnode with x>0 so its location is half of first node
which is = 1.208
But my question for that is when I tried 1.208 m, it was incorrect...so should the answer's units be m^-1?
That is my main problem...I think I am doing the process right but the units are confusing me.
For part two, I tried:
f=w/2pi = 2.50/2pi = .397
T= 1/f = 1/.397 = 2.51
I looked at a figure in my textbook, and the instance the standing wave vanishes is when t= (8/16)*T
so t=(8/16)*T = (1/2)*T=(1/2)*2.51= 1.255 s
But the units for w (if w is correct) was in s^-1, but I thought the units of angular frequency is in rad/s...so is 2.50s^-1 the frequency?
What am I doing wrong?