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Conceptual Question

  • Thread starter Red_CCF
  • Start date
  • #1
532
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This isn't a homework question but something I thought up but couldn't figure out.

If I tie a block to a rope at a very high elevation and throw the block down, what would the force-time diagram look like (from the moment the block is thrown) until the block begins to oscillate and how would I calculate the maximum force assuming that the rope has no dampening effect?

Thanks
 

Answers and Replies

  • #2
1,137
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i cant understant what oscillation you are talking about

is it free fall or something like pendulum motion

do we need to take account of variation of acceleration due to gravity
 
  • #3
610
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It sounds like the rope is attached to the top of a pole, or something. Correct? In that case, while the block is in freefall, there is only the force of gravity causing it to accelerate. Assuming the rope is not a bungee cord, the block would become a swinging pendulum when the rope goes taught. As a pendulum, the block experiences the force of gravity plus the force of of the rope.

And what do you mean by "maximum force"? Force of what on what at what time?
 
  • #4
532
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Hi

Sorry for not stating my question properly. I was thinking of a situation similar to what chrisbaird said, rope is attached to the top of a pole at one end and a mass at the other. The mass is dropped from the top of the pole; I'm wondering how I can calculate the maximum tension in the string. I imagined this situation more ideally in that the oscillation I was talking about was up and down (due to the elasticity of the string) not side to side like a pendulum.
 
  • #5
14
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I think you would have to look at the impulse.
When the rope snaps taught would be where the maximum force is. If you get an equation to describe the impulse at a given time and then differentiate, the zero's should give you the max and mins of force, the max being the max tension on the rope. The subsequent motion would then be damped SHM.
 

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