I started by assuming that the origin is at C.
So (by symmetry) the horizontal com is zero and the vertical com is the distance.
So work out the vertical com in terms of the midpoints of the sides. Side 4 drops out.
Does that help any?

(edited 4 years ago)

Reply 6

SeverusESnape

OP

16

Original post by mqb2766

I started by assuming that the origin is at C.
So (by symmetry) the horizontal com is zero and the vertical com is the distance.
So work out the vertical com in terms of the midpoints of the sides. Side 4 drops out.
Does that help any?

So you just changed the origin and got the right answer? I'm out by like 0.1 because root 5 over 5 is 0.4... I just chose A as my origin which SHOULD give me root 5 over 5. Can you post your working? Have you rounded your values?

Reply 7

mqb2766

21

Original post by SeverusESnape

So you just changed the origin and got the right answer? I'm out by like 0.1 because root 5 over 5 is 0.4... I just chose A as my origin which SHOULD give me root 5 over 5. Can you post your working? Have you rounded your values?

Tbh, I didn't fully understand your working. Can you annotate it to explain it a bit better. I didn't round, as using surds was reasonably straightforward.

You're correct, that it should not matter where the origin is, but placing it at C is an obvious place which simplifies the calculation. If I was you, I'd try reworking it with the origin at C. Happy to help you with your work, but I'm not posting solutions.