If F is the breaking force of a wire, what will be the breaking force for (a) two parallel wires of the same size (b) for a single wire of double the thickness?

Explanation

(a) When two wires of the same size are suspended parallel, then the breaking force of each wire being F, the breaking force of two wires in parallel will be `F+F = 2F`.
(b) `Y=F/(pi r^(2)) xx l/(Delta l)` or `F=(Y pi r^(2)Delta l).(l) or F prop r^(2)`
when `r' = 2r`, then `(F')/F = ((2r)^(2))/(r^2) = 4 or F' = 4F`.