Solve Rotational Motion Homework: Pulleys A, B, C

AI Thread Summary
The discussion revolves around solving a homework problem related to rotational motion involving pulleys A, B, and C. The user initially struggles with the lack of acceleration information and the differences in angular and linear velocities for compound and contact pulleys. They attempt to use the formula s = rδ to find the angular displacement but realize they need information about pulleys B and C for the complete solution. After receiving guidance from another user, the original poster successfully solves the problem. The thread highlights the importance of understanding the relationships between linear and angular motion in pulley systems.
freshbox
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Homework Statement


Attached 1st pic is the question, 2nd pic is the formula

PS: I am sorry if i have posted on the wrong section.

The Attempt at a Solution


My understanding for this question is for compound pulley, angular velocity is the same, linear velocity is different. For pulleys in contact, linear velocity is the same and angular velocity is different.

Since in this case, A/B are compound pulleys whereas B/C are contact pulleys.
But the question did not give me any acceleration info on any of the pulleys, so I don't know where to start..

The only info that I can gather is:

ωi=0m/s²
s=17m
t=20s

So I tried to use s=rδ formula.
17=0.15δ
δ=113.33

Although I managed to get "1" of the answer, but the info I used was all from pulley A but the answer they want is gears B/C so I'm abit confused here.
Hope someone can help me out.Thanks.
 

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welcome to pf!

hi freshbox! welcome to pf! :smile:
freshbox said:
… the question did not give me any acceleration info on any of the pulleys, so I don't know where to start..

start by finding the (linear) acceleration of the weight D :wink:
 
Hi tiny-tim thanks for the tip, i solved the problem already :)
 

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