Question

A car is moving forward and breaks suddenly. A bag in the backseat flies forward, what is the force that acts on the bag?

1) Breaks

2) Road

3) Chair

Or is there something else?  

Answer 1

It is because of inertia. We wanted to remain in the same position unless some external force act on us. In this case the car was moving forward so the bag will also moving forward with same velocity as the car. When break applies, the car slow down due to breaking force also the bag will slow down as like the car, but there is no external force on bag as like break on car. So bag want to remain in same motion as before the break. So bag will move with higher speed as earlier but car at slow. So the bag will flies forward.