PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A city bus starts suddenly, moves a short distance, and then stops abruptly at a traffic light. Answer the following questions related to the motion of the passengers inside the bus.
(i) State Newton’s First Law of Motion.
(ii) Using the law stated in part (i), explain why the passengers tend to fall backward when the bus starts and fall forward when it stops.
(iii) Describe in detail how a seat belt protects the passengers during the sudden stop mentioned above.
(iv) Suggest one additional safety device (other than seat belts) used in motor vehicles that relies on the same physical principle, and explain its working briefly.