64. A steel ring of radius r and cross-section area ‘A’ is fitted on to a wooden disc of radius R
A steel ring of radius r and cross-section area ‘A’ is fitted on to a wooden disc of radius R(R>r). If Young’s modulus be E, then the force with which the steel ring is expanded is
(a) AE(R/r) (b) AE{(R-r)/r}
(c) (E/A){(R-r)/A} (d) (Er)/(AR)
ANSWER-b
(4)