string or rope will break apart if it is placed under too much tensile stress $[$see Eq$.(11\mathrm{.}8)].$ Thicker ropes can withstand more tension without breaking because the thicker the rope, the greater the cross$-$sectional area and the smaller the stress. One type of steel has density and will break if the tensile stress exceeds $.$ You want to make a guitar string from $4\mathrm{.}0$ g of this type of steel. In use, the guitar string must be able to withstand a tension of $900$ N without breaking. Your job is to determine $($a$)$ the maximum length and minimum radius the string can have; $($b$)$ the highest possible fundamental frequency of standing waves on this string, if the entire length of the string is free to vibrate.