- #1
Aliasa
- 16
- 1
Homework Statement
Find the center of mass of a uniform sheet in the form of a circular disc
with a hole bounded by the equations x^2 + y^2 ≤ 1 and (x - 1/2)^2 + y^2 ≥ (1/16).
Aliasa said:That is all the info given.
SteamKing said:Can you find the area of the figure?
Yes, but can you find the area? This is a disk with a hole in it. It would be a good idea to at least draw a picture of the "hole bounded by the equations x^2 + y^2 ≤ 1 and (x - 1/2)^2 + y^2 ≥ (1/16)." Those boundaries are circles. Can you graph the circles?Aliasa said:That is all the info given.
You are misunderstanding the question. The metal template is very precisely defined by the two equations; there is no range of possible shapes and sizes. The centre of mass is an exact point. The two equations together define the metal surface, the hole is where there is metal missing.Aliasa said:It turns out the question is horribly worded. The sheet is bounded by the former equation, while hole by the latter -_-. Since the equations are inequality, by taking density into account, I feel the center of mass should be a range too. The hole can have a max radius of .5, sheet, 1. Hole can have a min radius of 1/4, when the sheet can have a minimum of 3/4.
Aliasa said:If that is the case then the question is trivial. I have solved it if those equations represent what you say. But doing that only takes me 5 minutes or less, which I can't understand. All the other questions on the assignment take in excess of 3 hours.
Yes. That's correct. Nice job.Aliasa said:The answer is (-1/30,0) btw.
The center of mass of a disc with a hole is the point at which the disc would balance if it were placed on a pivot at that point. It is the average position of all the mass in the disc.
The center of mass of a disc with a hole can be calculated using the formula: x = (M1x1 + M2x2) / (M1 + M2), where x is the position of the center of mass, M1 and M2 are the masses of the disc and the hole respectively, and x1 and x2 are the distances of the disc and the hole from a reference point.
Yes, the shape and size of the hole do affect the center of mass of a disc. The closer the hole is to the edge of the disc, the more it will shift the center of mass towards it. Similarly, a larger hole will have a greater effect on the center of mass compared to a smaller hole.
No, the center of mass of a disc with a hole will always lie within the boundaries of the disc. This is because the center of mass is calculated by taking into account the positions and masses of all the particles within the disc, and the hole is a part of the disc's boundary.
The concept of the center of mass of a disc with a hole is used in various practical applications, such as in designing objects with balanced weight distribution, determining the stability of structures, and calculating the motion of objects. It is also useful in physics and engineering calculations involving rotational motion and torque.