5. The position of a particle is given by the equation st3-6t2 +9t where t is measured in seconds and s is in meters. A) Find the velocity at time t. B) What is the velocity at 2s? At 4s? C) When is the particle at rest? D) When is the particle moving forward (that is in the positive direction)? E) Find the acceleration at time t F) Find the acceleration at 4s? G) When is the particle speeding up? When is it slowing down?