You can't change the direction of playing an instrument. So there wouldn't be any change in velocity. But there can be a change in speed. So finding the acceleration of playing is possible. It would just be the change in the speed. If you start playing slow and then began increasing your speed to playing fast, you have just accelerated. You make a change in your velocity or speed. There is the whole thing about angles. If you lift your finger too high, it would be a little difficult to play fast. But it would be great if you were playing slow. And if you lift your fingers not high enough, then your playing will just sound like a blur if you were playing fast. But if you lift your fingers just the right hight, you get the perfect speed of sound, no matter if you are trying to play fast or slow. You can actually calculate the acceleration by using the formula and plugging in the numbers and then solving.