What will change the velocity of a periodic wave?

If it's a mechanical wave, then its speed depends on the physical characteristics of the medium.

If it's an electromagnetic wave, then its speed depends on the
electrical characteristics of the medium.

Either way, the properties of the medium determine the wave speed.
You want to change the speed ?  You have to change the properties
of the medium.

Iread this book last year so take this with a grain of salt.gene jumps from the tree to compete with finny due to the fact that gene is always trying to do better than finny. he is put under the grasp of peer pressure due to finny almost forcing him to do this. ever since he first jumped finny kept pressuring him to jump since he thought gene enjoyed jumping.rather than uses this answer you should probably just reread chapters 3-4