The velocity of a rocket is given by

v(t) = 2000 * ln [ 14 * 10⁴ / (14 * 10⁴ 2100 * t) ] - 9.8 * t, where 0 second

Using the approximated formula for computing the second derivative:

f (@ Xi) = [ f(@Xi+2) 2 f(@Xi+1) + f(@Xi) ] / (x)²

Compute the JERK ( or compute the second derivative of velocity ) at time t = 16 seconds, using the (varying) step size = 2 seconds to 0.03125 second (such as keep reducing the step size by a factor of 2)