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# Confusing pulley question m1 Watch

1. Hi for part b for this question, I am stuck on it. So I have already answered a but for b how do I know when the string breaks. How do you find v because the string can break at any moment right? I know that s is h and u is 0 and a is 49/150 ms-2. Next I am not sure. Thanks in advance.
2. (Original post by coconut64)
Hi for part b for this question, I am stuck on it. So I have already answered a but for b how do I know when the string breaks. How do you find v because the string can break at any moment right? I know that s is h and u is 0 and a is 49/150 ms-2. Next I am not sure. Thanks in advance.
the acceleration cannot be positive
3. (Original post by coconut64)
Hi for part b for this question, I am stuck on it. So I have already answered a but for b how do I know when the string breaks. How do you find v because the string can break at any moment right? I know that s is h and u is 0 and a is 49/150 ms-2. Next I am not sure. Thanks in advance.
You're meant to find the distance in terms of h.

So use s = h and do SUVAT to find v in the same way as you would if you had s equal to some number.

Try this and post your working if you get stuck.
4. (Original post by drandy76)
the acceleration cannot be positive
The OP first has to find the velocity when the string breaks.

Taking left as positive, the acceleration will be positive before the string breaks.
5. (Original post by notnek)
The OP first has to find the velocity when the string breaks.

Taking left as positive, the acceleration will be positive.
ahh thought they were focusing soley on the distance after the spring breaks
6. Need to use the SUVAT equations to finding velocity at the point the string breaks. Then use SUVAT again to find the distance moved from that point. The only force once the string breaks acting on A in the horizontal direction is the frictional force.
7. (Original post by drandy76)
the acceleration cannot be positive
If you sub in 0.2 into the equation you fpund in a it wil. The markscheme says so as well.
8. (Original post by B_9710)
Need to use the SUVAT equations to finding velocity at the point the string breaks. Then use SUVAT again to find the distance moved from that point. The only force once the string breaks acting on A in the horizontal direction is the frictional force.
How do I find u ? I know that v would be 0 and value of a and s. Thanks
9. (Original post by notnek)
The OP first has to find the velocity when the string breaks.

Taking left as positive, the acceleration will be positive before the string breaks.
But i have no idea when the string breaks though. I domt know what u is . thanks
Can you upload the corresponding mark scheme?
Thanks
Attached Images
11. in a hurry.pdf (647.8 KB, 50 views)
12. (Original post by depymak)
Can you upload the corresponding mark scheme?
Thanks
This is beyond M1.
13. (Original post by coconut64)
But i have no idea when the string breaks though. I domt know what u is . thanks
You said u = 0 in your first post which is correct.

You're starting from t = 0 when the particle is at rest. And you need to find the velocity of the particle just as the string breaks, which is when s = h.
14. yes, I should know. Thanks.
(Original post by notnek)
This is beyond M1.
thus,
v2=u2-2|a|s
has to be used twice.
At first with the predefined acceleration and zeroth initial velocity, where s=h,
then we redefine acceleration of A, reuse the above equation where final velocity is.. and distance is unknown.
I like question c, though.
15. (Original post by coconut64)
If you sub in 0.2 into the equation you fpund in a it wil. The markscheme says so as well.

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