An object comprises of a uniform ring of radius R and its
uniform chord AB (not necessarily made of the same material)
as shown. Which of the following can not be the centre of
the mass of the object ?
Answers
Answer: the centre of the radius r.
Explanation: Since centre of gravity of a body is the point where the algebraic sum of moments of weights of all particles constituting the body is zero, so the centre of gravity lies outside it.
Answer:
(R/root2,R/root2)
Explanation:
first of all draw a circle of radius R. then construct a random chord ab. let the center of the circle be O and that of chord be X. now we know that the centers of mass of the circle and the chord lie on their geometric centers.
therefore the center of mass of the circle and chord is at O and X respectively. We can assume the entire mass of the figures to be concentrated at their centers of mass. This implies that the center of mass of the system will lie on the line joining O and X. (R/3,R/3) and (R/4,R/4) lie on OX. but (R/root2,R/root2) does not lie on OX. therefore option b, c d are not possible.