Tricky Center of Mass Problem

In summary, the center of mass of a uniform circular plate with a circular hole cut out of it can be determined by treating the cut out portion as a disc of negative mass with the same magnitude of uniform mass density. This allows for a simple subtraction of the two discs to find the position of the center of mass in terms of the radius R, with the center of the smaller circle located at a distance of 0.80R from the center of the larger circle. Integration is not required for this problem.
  • #1
sweatband
16
0

Homework Statement



A uniform circular plate of radius 2R has a circular hole of radius R cut out of it. The center C' of the smaller circle is a distance 0.80R from the center C of the larger circle. What is the position of the center of mass of the plate?

Homework Equations



Hints:
subtraction is to be used
answer expressed in terms of R

The Attempt at a Solution



I believe integration is required to solve this, but I do not know where to begin.
 
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  • #2
If anyone knows of a link they could send me that could lead me in the right direction, please let me know!
 
  • #3
sweatband said:
I believe integration is required to solve this, but I do not know where to begin.

On the other hand, I believe, if you know that centre of mass of a circle is at its centre, you do NOT need to worry about integration: addition (or, 'subtraction' as the hint says) will suffice!

HINT: The portion that has been cut out, you can assume that a disc of negative mass was superimposed in that portion! (Of course, of same magnitude of uniform mass density as the first one.)
 

What is the "Tricky Center of Mass Problem"?

The "Tricky Center of Mass Problem" is a physics problem that involves determining the center of mass of a system of objects with irregular shapes and/or varying densities. It can be a challenging problem due to its complexity and the need for careful calculations.

Why is the center of mass important?

The center of mass is important because it helps us understand how an object will move and behave when subjected to external forces. It is also a crucial concept in fields such as mechanics, astronomy, and engineering.

How do you calculate the center of mass?

The center of mass can be calculated by dividing the total mass of the system by the sum of the individual masses, multiplied by their respective distances from a chosen reference point. This can be expressed as an equation: center of mass = (m1d1 + m2d2 + ... + mndn) / (m1 + m2 + ... + mn), where m is the mass and d is the distance from the reference point.

What makes the "Tricky Center of Mass Problem" challenging?

The "Tricky Center of Mass Problem" can be challenging due to the irregular shapes and varying densities of the objects involved. This requires careful consideration and precise calculations in order to determine the correct center of mass.

What are some tips for solving the "Tricky Center of Mass Problem"?

Some tips for solving the "Tricky Center of Mass Problem" include breaking down the system into smaller, simpler parts, using symmetry to simplify the problem, and double-checking your calculations to ensure accuracy. It is also helpful to draw diagrams and label all relevant quantities in order to visualize the problem and make the calculations easier.

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