A car moves on a straight road such that its position from a reference point is given by the following function: { x(t) = 3 + 5t + 2t2 + 0.4t3, y(t) = 0, z(t) = 0 }

Find the acceleration, in meters per square second, in the x-direction at t1 = 0.85 sec.
Find the acceleration, in meters per square second, in the x-direction at t1 = 0.85 sec.
Find the average velocity, in meters per second, in the x-direction between t1 = 0.85 s and t2 = 1.95 s.
Find the average acceleration, in meters per second squared, in the x-direction between t1 = 0.85 s and t2 = 1.95 s.