STRAIN AT THE MIDDLE POINT IS ASKED MAN!!!

 

SO,

 

   STRAIN=STRESS/Y

 

STRESS=FORCE/AREA

 

THUS WE REQUIRE THE FORCE AT THE MIDDLE POINT

 

CONSIDER THE ROD CUT INTO TWO HALVES  OF LENGTH  =L/2

 

FORCE AT THE MIDDLE ARE  THE ACTION REACTION FORCES BETWEEN THE TWO ASSUMED RODS.

 

AS THE ROD IS ROTATING ALONG THE AXIS WHICH IS AT THE END OF ONE ROD(one of the assumed rods).

 

THE SECOND ROD WILL EXERT A FORCE(centripetal) ON THE FIRST ROD.

 

BY  C.O.M  LET THE SECOND ROD BE A PARTICLE AT IT'S geometric CENTRE WHICH IS AT A DISTANCE OF3L/4 FROM THE AXIS.

THUS

 F=(M/2)*(3L/4)*W^2

 

THUS

STRAIN=  F/AY

 

THUS U GET THE ANSWER MAN!!!!!!!

 

DID U UNDERSTAND??