1. The position of a particle is given by the equation s(t)=1³-61² +91 where t is measured in seconds and s in meters. a. Find the velocity at time r. (2 points) b. What is the velocity after 2 seconds and after 4 seconds? (4 points) c. When is the particle at rest? (6 points) d. When is the particle moving forward (that is, in the positive direction)? State your conclusion in a complete sentence. (9 points) e. Find the acceleration at time t. (2 points) f. Find the acceleration after 4 seconds? (2 points)