Aball whirls around in a vertical circle at the end of a string. the other end of the string is fixed at the center of the circle. assume that the total energy of the ball-earth system remains constant. (a) what is the tension in the string at the bottom?

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.