As part of an engineering project for class, Emma needs to make a wave on a rope to touch a switch on the bottom of a box. A wave generator is used to make the rope move in a wave motion. One machine is making a wave on a rope. The wave almost reaches a switch on another machine. Even when Emma turns the machine up to its highest power setting, the rope does not go up high enough to touch the switch. Emma cannot move the switch or the wave generator. What question could Emma investigate to help with her design?