An object of mass m=2 kg has a position given by r = (3+7i + 8t^3) where t is the time in seconds and the units on the numbers are such that the position components are in meters. Assume all numbers are exact (for instance, m=2 kg means m= 2.00000…kg ) At t=1 s, what is the magnitude of the acceleration on this object, in units of m/s^2 ? Enter the numerical answer without units. Your answer must be within 1% of the exact answer to receive credit.