Verification of truth – car starts suddenly, boy on back seat bends backward: "A boy is sitting on the back seat of a car. When the driver starts the car suddenly, the boy bends towards the backside." Choose the most accurate frequency.

Introduction / Context:
This question probes everyday physics (Newton’s laws) and how human bodies respond to sudden acceleration of a vehicle. It requires judging typicality rather than logical necessity.

Given Data / Assumptions:

• The car starts suddenly (forward acceleration).
• The boy sits on the back seat without special restraints other than a typical seatback.
• We assess what usually happens in such starts.

Concept / Approach:
By inertia (Newton’s first law), a body at rest resists change in motion. When the car accelerates forward, the seat pushes the boy’s lower back forward; relative to the car’s frame, his upper body tends to “lag,” giving the sensation/appearance of bending backwards.

Step-by-Step Solution:

Verification / Alternative check:
Real-world exceptions exist: if the boy anticipates and tenses forward, braces with hands, or if seatbelts/child restraints limit motion, the observable lean can be reduced or absent. Hence it is not “always.”

Why Other Options Are Wrong:
Always overstates, ignoring cases with restraints or anticipatory bracing. Sometimes understates; the effect is common. Never contradicts basic inertia.

Common Pitfalls:
Confusing the frame of reference (car vs. ground) and misreading “generally” vs. “always.”

Final Answer:
Generally