Physics intuition — apparent force in an accelerating car A boy is sitting on the back seat of a car. When the driver suddenly starts moving the car forward, the boy experiences a backward force — this happens _____. Choose the correct frequency.

Concept Due to inertia (Newton's first law), the boy's body tends to remain at rest when the car accelerates forward suddenly, producing an apparent backward (pseudo) force in the non-inertial car frame.

Implication Whenever there is sudden forward acceleration, this backward sensation occurs.

Final Answer Always.