KAPLAN discrete y = 0.01 sin (50x -2t), what is the amplitude and speed?

[shenf1]

Q: A traveling sinusoidal wave is described by

y = 0.01 sin (50x -2t)

in which the numerical constants are in SI units.What are the amplitude and speed of this wave, respectively? Answer = 0.01 m, 0.04 m/s2

METHOD 1
The point of this question was to see whether one understood all the components of the wave equation.
The general equation format is Y = Amplitude sin (kx-wt), where K = wave number and w = angular frequency

k = 2pi/l;; and w=2pf. That's what you need to know for this problem.

Then after solving for lambda you'll be able to use v= f *l; , wave velocity is then found.

METHOD 2
If the derivative of the wave function is taken, then the velocity would be v=-2A/50 cos(x-2t/50) or v= -2*.01/50 with a maximum and minimum velocity of +/- .0004m/s at maximum cosine values of -/+ 1.

So which of these methods/answers is correct?

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[orangetea]

Well they are both correct. It is just giving you two different ways of approaching the problem. I personally like the first one because it's a lot more straight forward

 

[shenf1]

Well they are both correct. It is just giving you two different ways of approaching the problem. I personally like the first one because it's a lot more straight forward

The answers are different by a factor of .01

 

[shenf1]

Q: A traveling sinusoidal wave is described by

y = 0.01 sin (50x -2t)

in which the numerical constants are in SI units.What are the amplitude and speed of this wave, respectively? Answer = 0.01 m, 0.04 m/s2

METHOD 1
The point of this question was to see whether one understood all the components of the wave equation.
The general equation format is Y = Amplitude sin (kx-wt), where K = wave number and w = angular frequency

k = 2pi/l;; and w=2pf. That's what you need to know for this problem.

Then after solving for lambda you'll be able to use v= f *l; , wave velocity is then found.

METHOD 2
If the derivative of the wave function is taken, then the velocity would be v=-2A/50 cos(x-2t/50) or v= -2*.01/50 with a maximum and minimum velocity of +/- .0004m/s at maximum cosine values of -/+ 1.

So which of these methods/answers is correct?
Anyone know the answer to this problem?