Can the kinetic friction be in the direction of acceleration? I am thinking of the example of a box on a flatbed truck accelerating to the right from rest. The box accelerates to the left due to the inertial force as seen by an observer on the truck where the kinetic friction is opposite to the direction of this inertial force and assuming that the inertial force is greater than the kinetic friction. My difficulty is trying to understand how would the kinetic friction be the cause of acceleration as seen by the ground? any clarification would be appreciated.