You are on the roof of a building. You reach your arm out over the edge of the building and toss a ball straight up. The ball goes up, reaches

a maximum height,and then falls down to the ground below, reaching the ground at a time of 4T.The graph above shows the velocity of the ball as a function of time, where positive is directed up, and we will take the acceleration to be a constant value of 10.0 m/s/s directed down. In this case, T = 1.60 s. Calculate the ball's average speed (m/s) for the 4T time period.