I'm trying to understand the two box problem, where a small box is stacked on top of a larger box. The larger box then experiences a push, causing both boxes to accelerate in the direction opposite to the applied force.
Now my understanding of the FBD of the smaller box is that there's Fg, Fn, which cancel out, and a force of static friction that supposedly causes the acceleration.
I can't seem to wrap my head around why friction would cause acceleration. Can anyone help me out? Thanks in advance!