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Finding Center of Mass

  • Thread starter heloudan
  • Start date
  • #1
2
0
A thin rectangular plate of uniform areal density σ = 3.13 kg/m2 has length of 44.0 cm and width of 26.0 cm. The lower left hand corner is located at the origin, (x,y)= (0,0) and the length is along the x-axis.
There is a circular hole of radius 7.00 cm with center at (x,y) = (16.00,11.00) cm in the plate

Calculate the x-coordinate of CM of the plate.!?
Calculate the distance of the plate's CM from the origin.!?



for some odd reason i can figure out any other problem but this one if someone could help me out that would be great
 

Answers and Replies

  • #2
117
0
do you have to calculate it?
you can hang it from two or more points to find the CM :-)
 
  • #3
2
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yes i have to calculate it i dont even know where to start
 
  • #4
rl.bhat
Homework Helper
4,433
7
Find the position vectors of the CM of rectangular plate and removed circular disc.
Let M be the mass of plate and m be the mass of the disc.
Position vector R1 of M = (022i + 0.13j). Mass M = σ*A. where A is the area of the plate
Position vector R2 of m = (0.16i + 0.11j) Mass n = σ*a ,where a is the area of the removed circular disc.
Then the position vector of CM of the remaining mass of the rectangular plate is
R = (M*R1 - m*R2)/(M - m)
 
  • #5
4,662
5
If you know the moment of inertia at any two points, can you use the principal axis theorem to triangulate the CM?
Bob S
 

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