A particle is moving along the r-axis. Its position at time t 2 0 is given by I(t) = + + + 3t + 2 where c is measured in feet and t is measured in seconds. (a) Find all values of t > 0 for which the particle is moving to the left. (b) Find the total distance the particle travels during the first 6 seconds. (c) Is the particle speeding up or slowing time at t = 4? (d) Find the maximum speed of the particle for 0