Compute the each part of given problem:
Problem: A rider of mass 50 kg sits on a toboggan of mass 70 kg. which in turn sits on a frictionless frozen pond. The coefficients of static and kinetic friction between the rider and the toboggan are 0.4 and 0.2 respectively. The toboggan in pulled along the pond with horizontal force F.
Part I: Find the maximum value of F for which the rider will not slide on the toboggan.
Part II: Find the accelerations of the toboggan and rider if F is twice this value.
Show all work, use additional paper if necessary.