Using your knowledge of momentum explain why cars are designed to have crumple zones?

Can someone explain to me how to do this problem ?

Consider two metallic rods mounted on insulated supports. one is neutral, the other positively charged. you bring the two rods close to each, but without contact, and briefly ground the the neutral rod by touching it with your hand. show answer correct answer what would be resulting charge (if any) on the initially neutral rod

Carbon 14 is a naturally occurring stable