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m3:what if a particle is attached to a stretched string whilst in a rough surface?

Should we assume at m3 level that the particle is moving under constant deceleration only due to the rough surface? A problem in the book had this condition and the solution assumed the particle was only experiencing deceleration due to the rough surface and not due to both the stretched string and rough surface. Attached the question(question 8), solution and my working showing that distance travelled would cause particle to enter the stretched string territory.
(edited 7 years ago)
Original post by thebrahmabull
Should we assume at m3 level that the particle is moving under constant deceleration only due to the rough surface? A problem in the book had this condition and the solution assumed the particle was only experiencing deceleration due to the rough surface and not due to both the stretched string and rough surface. Attached the question(question 8), solution and my working showing that distance travelled would cause particle to enter the stretched string territory.


It looks as if the book has failed to take into account that the string will stretch again. Just assumed that it doesn't and that all the motion on the rough surface will take place whilst the string is unstretched. This is not the case, as you've discovered - book's in error.

For the sake of doing the question, you'll have to assume that once the string goes slack, someone steps in and cuts it.
Original post by ghostwalker
It looks as if the book has failed to take into account that the string will stretch again. Just assumed that it doesn't and that all the motion on the rough surface will take place whilst the string is unstretched. This is not the case, as you've discovered - book's in error.

For the sake of doing the question, you'll have to assume that once the string goes slack, someone steps in and cuts it.


I see. The situation is quite difficult here. I hope it doesnt come up in an exam. Thanks a lot!

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