6. A motorboat is traveling at an initial velocity of 5.0 meter/second when it starts to accelerate opposite to the motion to arrive at the dock. Its acceleration is a(t) = -t meters/second. (a) What is the velocity function of the motorboat? (b) At what time does the velocity reach zero? (c) What is the position function of the motorboat? (d) What is the displacement of the motorboat from the time it begins to accelerate opposite to the motion to when the velocity is zero? (hint: suppose v(t) represents the velocity function, s(t) represents the distance function, recall that v(t) = = s(t) and a(t) = &v(t))