In the game, pushing a crate sets it moving forever (no friction). To stop it, you must apply an equal and opposite push at exactly the right moment. This mirrors real-world inertia: a moving object wants to stay moving. In car safety, this is why seatbelts and airbags exist — they provide the stopping force over time to reduce injury. The faster something moves, the more "push" (force × time) is needed to stop it.
When a crate hits a flat wall, the angle of incidence equals the angle of reflection (like light on a mirror). If a crate approaches a wall at 30° from the wall's surface, it rebounds at 30° on the other side. Try tracing the path: measure the incoming angle with a protractor on screen, predict the outgoing path, then test it!
Inertia isn't a number — it's a feeling of momentum. Every action in this game has an enduring consequence. A single over-push can send a crate ricocheting endlessly, damaging equipment. Restraint is a skill: knowing when not to push hard is just as important as knowing when to act. This is Newton's First Law in action: an object in motion stays in motion unless acted upon by an external force.