The reason you fall in a particular direction when a bus stops or starts is due to inertia — the tendency of an object to resist any change in its state of motion.
- When the bus brakes to stop: Your body tends to continue moving forward because it wants to maintain its original velocity. Hence, you fall forward.
- When the bus accelerates from rest: Your body tends to remain at rest while the bus moves forward, making you fall backward.
This demonstrates Newton’s First Law of Motion (Law of Inertia).