Instantaneous Center of Rotation Help Needed

AI Thread Summary
The discussion revolves around calculating the instantaneous center of rotation in a piston-cylinder-crank arrangement of an internal combustion engine. The user has converted the piston’s downward speed from 900 ft/min to 180 in/sec but encountered issues with the length of link AB, mistakenly using 8.5 inches instead of the correct measurement. They are trying to solve for the angular velocity of link AB, the velocity of point B on the crank, and the angular velocity of crank BC, but are confused by their results and the application of the Law of Sines. The user is also questioning how to find the angular velocity of crank BC without a vector. Overall, they seek clarification and assistance in resolving these calculations.
smashbrohamme
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The figure below shows the piston-cylinder-crank arrangement in an internal combustion engine. When the piston is in the position shown in the figure, it has a downward speed of 900ft/min.
I converted the 900ft/min to 180in/sec.

I did the whole problem but I realized I used the wrong length on link AB.

I used the 8.5in length for AB but I still encountered a problem on solving this problem with the vectors.

The three questions to answer are.
A. Find the Angular Velocity of link AB
B. Find the velocity of point B on the crank.
C. Find the Angular Velocity of Crank BC.

Now the vectors I have are shown in the next attachment, is this right?

Also everytime I try to solve for length AB i get some weird answer, shouldn't this be a simple LAW of SINES problem? I keep getting 9.5inches, which just doesn't make any sense at all.

Please help I just got off spring break and my mind is jumbled with pizza and video games lol.
 

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  • Rotation Problem 2..png
    Rotation Problem 2..png
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  • Center of Rotation Problem.png
    Center of Rotation Problem.png
    6.9 KB · Views: 576
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the second picture is the original problem with the vector converted.

and if C does not get a Vector, how could you find the angular velocity of crank BC, shouldn't is just be Wsys.?
 
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