Brass rod with a length of 1.40 m and a cross-sectional area of 2.00 cm2 is fastened end to end to a nickel rod with length L and cross-sectional area 1.00 cm2. The compound rod is subjected to equal andopposite pulls of magnitude 4.00E4 N at its ends. a) Find the length L of the nickel rod if the elongations of the two rods are equal. b) What is the stress in each rod

I think they use it at night because they want to avoid involving themselves in road accident while crossing the street. When there are reflective strips on their clothes, drivers do notice them even at far ends of the street since the strips will reflect the rays from the car lights to the driver,hence, the driver notifies that there is a pedestrian crossing and therefore slows down.