A Stretchable Resistor
Part A = 4R
Express your answer in terms of the wire’s original resistance R.
Resistance is equal to ρ * l/A, where ρ is resistivity, l is length, and A is the cross sectional area. A cylinder has a volume of πr2h. Doubling the length (h) while holding volume constant means that the cross sectional area will be cut in half. Since the length doubles and the cross sectional area is cut in half, the overall resistance increases by a factor of 4.