Explanation:

When a bus is moving at a high speed and suddenly stops, the passengers in the bus experience a jerk forward. This happens due to the inertia of the passengers.

Inertia:
Inertia is the tendency of an object to resist any change in its state of motion. It is a property of matter and is dependent on the mass of the object. An object at rest tends to stay at rest, and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an external force.

Key Points:
- When a bus is moving at a high speed, the passengers inside the bus are also moving with the same speed and in the same direction as the bus.
- As the bus suddenly stops, an external force is applied to the passengers, causing them to experience a change in their state of motion.
- According to Newton's first law of motion, the passengers tend to resist this change in motion due to their inertia.
- The passengers continue to move forward with the same speed and in the same direction as the bus was moving before it stopped.
- However, the bus comes to a sudden halt, causing the passengers to collide with the seat or any other object in front of them.
- This collision results in a jerk forward for the passengers, as they suddenly decelerate due to the force exerted on them by the seat or any other object in front.
- The inertia of the passengers is the reason why they tend to keep moving forward even after the bus has stopped.
- This is also the reason why it is important for passengers to wear seat belts in vehicles. Seat belts help restrain the forward motion of passengers during sudden stops, reducing the risk of injuries.

Conclusion:
The jerk forward experienced by a passenger when a bus moving at a high speed suddenly stops is due to the inertia of the passenger. The passenger tends to resist the change in motion and continues to move forward until an external force, such as the seat or any other object, stops their forward motion.