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**Q.**

*In the arrangement shown in fig. the ends P and Q of an inextensible string move downwards with uniform speed u. Pulleys A and B are fixed. The mass M moves upwards with a speed.*

__ANSWER PROVIDED BY MY TEXT__In the diagram ##vcos\theta=u## therefore ##v=u/cos\theta##

__HOW I TRIED TO DO THE PROBLEM:__

Here both the ##usin\theta## cancel out but the component ##ucos\theta## of both the vectors

**u**add up. Therefore ##2ucos\theta=v## or ##v=2ucos\theta##

But this is a completely different answer regarding the former one, and the latter answer is marked wrong and the former correct. Why can't we add up the vectors like the latter case?

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