High School Physics Question!

Dunkaroos

Please help. I'm having difficulty with this problem. My book offers an answer but no explanation. Thanks for helping.


I have the answer if you guys want it.

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pizzasky

Note that the wave is moving to the right. Hence, translate the whole curve slightly to the right to determine where point P will eventually be.

kudos213

Yes, but doesn't each point on the wave maintain it's position in the positive x direction? It's only the y component of each point which changes. Anyone else have any idea?

Hootenanny

Yes, the point P oscillates only in the y direction, so as the wave moves to the right, will point P move up or down?

~H

kudos213

negative y hat

Hootenanny

Yes, I suggest we let the OP finish of the question.

~H

kudos213

word...i'm still new here i.e. learning the ropes. how could we mathematically solved this question?

Hootenanny

You couldn't, there is no data given (velocity/ displacement / time).

~H

DaveC426913

This question actually somewhat ambiguous, and as such the OP might get the wrong advice and answer.

Depending on how you interpret "point P", your answer will be different!
a] Point P is a physical point on the rope.
b] Point P is an imaginary point on the wave.

Pizzasky interpreted it as a], but others interpreted it as b].

I'm am 99.9% certain a] is correct. So, yes, follow Kudos and Hoot's guidance.

Hootenanny

The OP said they have the correct answer, it would be helpful if he/she could post it to clear the matter up. But I agree with Dave, it is an ambiguous question, I was assuming point P is a physical point on the wave.

~H

skywolf

if the wave is going to the right, then shouldnt the answer be c?
......
maybe im missing something

Hootenanny

That is what we were discussing, I'll refer you to posts #4,5,6,7

~H

Dunkaroos

The answer key gives choice C.

Anyone care to explain? Thank you all.

DaveC426913

OK. That clears up what they're asking. Point P is a physical point on the rope. Pretend it's a spot of paint.

Now, as the wave travels down the rope, how will that spot of paint move?

Think of this: the rope is tied off the right side to a lamppost. Your friend is off to the left, holding the rope, waving it up and down, creating the wave. (Note that the rope does not actually go anywhere - he can wave all he wants, but the rope will remain in our field of vision).

NOW what will the spot of paint do?