4. The position of a point on a line is given by the equation s(t) = t - 6t + 9t - 4, where s is measured in metres and t in seconds. (2 marks each) a. What is the velocity of the point after 2 seconds? b. What is its acceleration after 4 seconds? c. Where is it when it first stops moving? d. How far has it travelled when its acceleration is 0? e. After 2 second, is it moving toward or away from the origin?