Date page- feud oa sprihg

so work done by the ext force is not zero then how u applied the Law of cons of mechanical energy here

sir here in this ques although conservative forces are present but we are applying an external force that displaces the spring and mass

thnx sir the question is understood

also from where 1/2*m*y*y came

sir how did u took y/2 why we didn't take y

see the attached files

see the attached files

see the attached files

see the attached files

see the attached files