Instantaneous Center of Rotation Help Needed

In summary, The conversation discusses a problem involving a piston-cylinder-crank arrangement in an internal combustion engine. The initial downward speed of the piston is 900ft/min, which is converted to 180in/sec. However, it is later discovered that the wrong length was used for link AB. The three questions to answer are finding the Angular Velocity of link AB, the velocity of point B on the crank, and the Angular Velocity of Crank BC. The vectors for the problem are shown in an attachment, but there is uncertainty about their accuracy. The conversation also mentions difficulty in solving for the length of AB and confusion about finding the angular velocity of crank BC.
  • #1
smashbrohamme
97
1
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.
 

Attachments

  • Rotation Problem 2..png
    Rotation Problem 2..png
    9.2 KB · Views: 466
  • Center of Rotation Problem.png
    Center of Rotation Problem.png
    6.9 KB · Views: 542
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  • #2
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.?
 

1. What is the instantaneous center of rotation?

The instantaneous center of rotation is the point in a moving body around which all other points on the body have zero velocity at a single instant in time. It is essentially the center of rotation at a specific moment.

2. Why is the instantaneous center of rotation important?

The instantaneous center of rotation is important because it helps us understand the motion of a body at a specific instant in time. It can also help us determine the velocity and acceleration of different points on the body.

3. How is the instantaneous center of rotation calculated?

The instantaneous center of rotation is calculated using a method called "instantaneous velocity analysis." This involves drawing tangent lines at two points on the body's path and finding their intersection point, which is the instantaneous center of rotation.

4. Can the instantaneous center of rotation change?

Yes, the instantaneous center of rotation can change as the body moves. It is a dynamic point that changes as the body's motion changes.

5. What are some real-world applications of understanding the instantaneous center of rotation?

Understanding the instantaneous center of rotation can be useful in various fields, including engineering, biomechanics, and robotics. It can help engineers design better machinery and structures, aid in analyzing human and animal movement, and improve the performance of robots and other mechanical systems.

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