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# M1 question Watch

1. A string passes over a rough cylindrical rail, and objects of mass 10kg and mkg attached to the ends hang vertically on either side. Because of friction between the string and the rail, when the objects are in motion the tension in the string on the descending side is twice the tension on the ascending side. Find the acceleration of the system in the cases
(a) m=2 (b) m=24 (c)m=12

For (c) I get -2.45 but it's not the answer, an explanation about how to answer this question would be a great help. This whole section of the M1 book (OCR Mechanics 1, Revision Excercise 2) is a bit weird compared to the entire book as I have to do things it hasn't taught me to do and seem wrong to get right answers in questions.

Thanks
2. Draw a picture. You have the governing equation F=ma

for a) you have F = mg - Tension

You know the tension on the descending side is x2 than the other side so you have

10*g - 2T = 10a
2*g - T = 2a

Rearrange & you'll get your result.

Do the same for b) & c).
3. (Original post by Ewan)
Draw a picture. You have the governing equation F=ma

for a) you have F = mg - Tension

You know the tension on the descending side is x2 than the other side so you have

10*g - 2T = 10a
2*g - T = 2a

Rearrange & you'll get your result.

Do the same for b) & c).
got (a) and (b), but i did this for (c) and got -2.45, but it says answer is 0

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