When drawing the free body diagram (FBD) of a block resting on a friction or frictionless surface, there are two cases. In case 1, we draw a force of 20N in the right direction at the back of the block. In case 2, we draw a force of 20N in the right direction at the front of the block (not the top side). In case 1, there is a push force, and in case 2, there is a pull force. Is it right to think that we can draw a push force or pull force in either direction? Shouldn't it affect the FBD because in case 1, the force goes through the body and in case 2, it is just a pull?