Read the following passage and answer the question below <br><br>
An object remains in the state of rest or uniform motion in a straight line unless compelled to change that state by an applied force. In other words all objects resist a change in their state of motion. In a qualitative way, the tendency of undisturbed objects to stay at rest or to keep moving with the same velocity is called inertia. That is why the first law of motion is also called law of inertia.
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Certain experiences that we come across while travelling in a motorcar can be explained on the bases of this law of inertia. We tend to remain with respect to the seat until the driver applies a braking force to stop the motorcar. With the application of brakes, the car slows down but our body continues in the same state of motion because of inertia.<br><br>
QUESTION : When we stand in a stationary bus and the bus starts suddenly, we are thrown backwards, this is because of