# M3 elastic springs and strings

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#1

For part c we know the velocity of the particle when the string becomes slack but if I use suvat equations I don't get the correct answer, why is this?
0
3 years ago
#2
(Original post by moz4rt)

For part c we know the velocity of the particle when the string becomes slack but if I use suvat equations I don't get the correct answer, why is this?
You can use SUVAT as long as you remember that the particle has already moved before the SUVAT starts, and that you must add that to your SUVAT answer. Post your working if struggling.
0
3 years ago
#3
(Original post by moz4rt)

For part c we know the velocity of the particle when the string becomes slack but if I use suvat equations I don't get the correct answer, why is this?
I wouldn't recommend using Suvat because the tension in the string will vary and hence the resultant force and accleration will vary. Try using an energy method

EDIT: Yes you can use suvat but only after the string is slack
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#4
Is the force acting in the opposite direction to motion mg/2 so the equation v^2=u^2+2as becomes gl/4=mgs, but the distance shouldn't be in terms of m
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#5
ahah nvm lol a=F/m
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