While a guitar string is vibrating, you gently touch the midpoint of the string to ensure that the string does not vibrate at that point. which normal modes cannot be present on the string while you are touching it in this way?

Asailboat is traveling to the right when a gust of wind causes the boat to accelerate leftward at 2.5m/s2 for 4s. after the wind stops, the sailboat is traveling to the left with a velocity of 3.0m/s.assuming the acceleration from the wind is constant, what was the initial velocity of the sailboat before the gust of wind? answer using a coordinate system where rightward is positive.