Rotational Motion Question 163
Question: $(n-1)$ equal point masses each of mass m are placed at the vertices of a regular n-polygon. The vacant vertex has a position vector a with respect to the centre of the polygon. The position vector of centre of mass is
Options:
A) $-\frac{1}{(n-a)}a$
B) $\frac{a}{(n+1)}$
C) $\frac{a}{n}$
D) $\frac{n}{a+1}$
Show Answer
Answer:
Correct Answer: A
Solution:
[a] Let the C.M.
be ‘b’.
Then,
$\frac{(n-1)mb+ma}{mn}=0\Rightarrow b=-\frac{1}{n-1}a$
