A uniform rod AB of length L is acted on by 2 forces $F_1$ and $F_2$ at the ends respectively.  The Young’s modulus is Y, cross-section area is A and length L. Mass of the rod is M. Choose the values of the extensions in column –II for the given values of  $F_1$ and $F_2$ in column –I.

	Column – I		Column – II
A)	If ${\text{F}}_{\text{1}}{\text{= 2Mg; F}}_{\text{2}}\text{= Mg}$	P)	extension is zero
B)	If ${\text{F}}_{\text{1}}{\text{=\hspace{0.17em}Mg; F}}_{\text{2}}\text{= 0}$	Q)	extension in rod is $\frac{\text{3M}g\text{L}}{2\text{AY}}$
C)	Instead of  $F_1$ and $F_2$  acting the rod is hanging freely from a ceiling of an elevator which is accelerating upwards with an acceleration g, then	R)	extension in rod is $\frac{\text{M}g\text{L}}{2\text{AY}}$
D)	Instead of  $F_1$ and $F_2$ acting the rod is hanging freely from a ceiling of an elevator which is accelerating downwards with an acceleration g, then	S)	extension in rod is $\frac{\text{M}g\text{L}}{\text{AY}}$