Video narration
You push a classroom desk, and it starts sliding across the floor. Friction acts against that motion. On a 50-kilogram box, weight pulls down and the floor's normal force pushes up; they balance. If only its straight-line motion matters, treat the box as a point; size and rotation don't matter. But the push alone doesn't decide what changes. The net force does. Push right with 200 newtons; friction pulls left with 92. That leaves 108 newtons right, so the box accelerates right. If push and friction are equal, net force is zero: a still box stays still, but a moving box keeps the same speed. If push is greater, it accelerates with the push. If friction is greater, a box moving right slows; it doesn't instantly reverse. With the same mass, a bigger net force means greater acceleration. Like your desk, net force-not just the push-changes motion.