[单选题]
A copper wire is fou:q ,zp)pgxi7w-:5 src8 yxubxnd to break when subjected tr5a7 tkylf(. 5fnp,f to minimum tension of 36 N. If the wire diameter were half as great, we would expect the wire to break when subjected to a minf(ff5k rl.,ynat tp7 5imum tension of