(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Please refer diagram attached.

The pulleys are moving down with constant speed u each. Pulleys are light , string ideal. What is the speed with the mass moves up?

2. Relevant equations

3. The attempt at a solution

Now, I got the answer as ucosΘ, obviously. But the answer is u/cosΘ.

the solution too is given. But I feel that the latter is wrong as the velocity goes to to infinity as the mass goes upwards. Please tell me which is correct.

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# Pulleys moving down with constant speed

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