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I am doing

**m= ukmg*L\v*squared**but it is not working, am I suppose to find a new velocity or something. Any help appreciated.

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In summary, Oliver, weighing 90.0 kg, uses a 4.60 m long rope to pull Jordan, weighing 53.6 kg, across the floor with a friction coefficient of 0.200. Jordan signals to Oliver to stop by "plucking" the rope, sending a wave pulse forward along the rope. The pulse reaches Oliver 149.0 ms later. According to the given formula, the mass of the rope can be calculated by using the tension in the rope (which equals the friction force) and the speed of the pulse. The equation used is m_{rope} = \frac{\mu m_{person} g L}{v^2}. After some confusion and clarification, it is determined that

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I am doing

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Why do you say it is not working? Where did you get that equation and what do the variables mean?

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uk= 0.2000

m= 53.6 kg

g= 9.8

v= 1.14

L=4.60

It seems like a very easy question but I don't know where I am messing up.

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its mass...

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M=uk*m*g*L\v^2

so I'm stuck also. You'll have to hope someone else does since you haven't explained it.

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- #9

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There's nothing wrong with that equation, which is derived from the formula for the speed of a wave (or pulse) on a stretched rope:macgirl06 said:I am doingm= ukmg*L\v*squaredbut it is not working, am I suppose to find a new velocity or something.

[tex]v^2 = \frac{T}{\rho}[/tex]

Where T is tension in the rope (which equals the friction force [itex]\mu m_{person} g[/itex]) and [itex]\rho = m_{rope}/L[/itex].

I'll rewrite that equation like this:

[tex]m_{rope} = \frac{\mu m_{person} g L}{v^2}[/tex]

v should be the speedmacgirl06 said:

uk= 0.2000

m= 53.6 kg

g= 9.8

v= 1.14

L=4.60

It seems like a very easy question but I don't know where I am messing up.

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- #12

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To find the speed of the pulse just use the distance it travels (the length of the rope) and the time it takes (which is given).macgirl06 said:

Yes.e(ho0n3 said:

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k got it, just a calculational error on my part. Thanks again for the clarification...:)

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