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# M1 past paper pulley question help watch

1. Hi,

Please could someone help me with this mechanics question, I'm very stuck

There's a pulley with a mass of 0.4kg on one end and 0.3kg on the other end. Both ends are 1m from the ground.

The first part was to work out the tension in the string and the acceleration which I've done.

I'm stuck on the 2nd part: when the masses have been moving for 0.5 secs the string breaks. Find the further time that elapses until B (the 0.3kg mass) hits the floor.

Thanks
2. (Original post by VioletPhillippo)
Hi,

Please could someone help me with this mechanics question, I'm very stuck

There's a pulley with a mass of 0.4kg on one end and 0.3kg on the other end. Both ends are 1m from the ground.

The first part was to work out the tension in the string and the acceleration which I've done.

I'm stuck on the 2nd part: when the masses have been moving for 0.5 secs the string breaks. Find the further time that elapses until B (the 0.3kg mass) hits the floor.

Thanks
Please post any working you've done / ideas you have for the 2nd part.

3. This is my attempt, whether or not it is correct is something somebody here will need to verify. As soon as the string snaps, the mass is travelling under free gravity. Hence a = 9.8, at which point, the fact that it is 0.3kg becomes irrelevant. Upon solving the quadratic involving t, I got a negative and a positive value, I eliminated the negative (you cant go back in time) and kept the positive after rounding up to 2dp.
4. (Original post by PedanticStudent)

This is my attempt, whether or not it is correct is something somebody here will need to verify. As soon as the string snaps, the mass is travelling under free gravity. Hence a = 9.8, at which point, the fact that it is 0.3kg becomes irrelevant. Upon solving the quadratic involving t, I got a negative and a positive value, I eliminated the negative (you cant go back in time) and kept the positive after rounding up to 2dp.
I don't have time to check your numbers right now but your working seems fine.

Do you know that your answer is wrong or just need us to check? I can check when I have time later.
5. (Original post by notnek)
I don't have time to check your numbers right now but your working seems fine.

Do you know that your answer is wrong or just need us to check? I can check when I have time later.
I have a good belief that it is correct, but I have a really bad mechanics teacher so I sometimes wonder if I have made a mistake.
6. (Original post by PedanticStudent)
I have a good belief that it is correct, but I have a really bad mechanics teacher so I sometimes wonder if I have made a mistake.
I've checked everything and It's correct!

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7. (Original post by PedanticStudent)

This is my attempt, whether or not it is correct is something somebody here will need to verify. As soon as the string snaps, the mass is travelling under free gravity. Hence a = 9.8, at which point, the fact that it is 0.3kg becomes irrelevant. Upon solving the quadratic involving t, I got a negative and a positive value, I eliminated the negative (you cant go back in time) and kept the positive after rounding up to 2dp.
very keen
8. (Original post by PlayerBB)
I've checked everything and It's correct!

Posted from TSR Mobile
Hurray! I'm trying my best to get over 90% in each past paper since the beginning of spec so that I can get the best possible AS result to take the pressure off next year, so I take any opportunity to advance knowledge.

Thanks for checking this for me!
9. (Original post by PedanticStudent)
Hurray! I'm trying my best to get over 90% in each past paper since the beginning of spec so that I can get the best possible AS result to take the pressure off next year, so I take any opportunity to advance knowledge.

Thanks for checking this for me!
No problem! and I think you'll be doing good in M1 as it's a tough question right there! And go for 100 UMS Also good luck with your As subjects, I am pretty sure you'll do fine if you put in the real hard work!

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Updated: January 22, 2016
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