You are standing in a moving bus, facing forward, when you suddenly slide forward as the bus comes to an immediate stop. What force caused you to slide forward?
A) the force due to friction between you and the floor of the bus
B) the normal force due to your contact with the floor of the bus
C) gravity
D) There is not a force causing you to slide forward.

Question

Quizplus · Accepted Answer

When the bus comes to an immediate stop, you slide forward not because of an external force acting in the direction of your motion, but due to your own inertia. Your body tends to maintain its state of motion (Newton's first law of motion), and no external horizontal force is applied to you to cause the sliding. The options A, B, and C describe forces that act in different contexts and do not directly cause the sliding forward motion when the bus stops.

You Are Standing in a Moving Bus, Facing Forward, When