[单选题]
A copper wire is found to break when 6xr f4q zu ;osaww/)y)subjected to minimu;bi wj*/lv9rxm 7,zl + fhrt-gu2p-u um tension of 36 N. If the wire diameter were half as great, wer;2-m*f +j ,x9wzuhlgl ut7r/ vupib- would expect the wire to break when subjected to a minimum tension of
