Physics
Physics
Problem
A city bus is stationary at a stop. The driver suddenly starts the bus and, a few minutes later, brakes sharply to avoid a speed-breaker. a. (i) State Newton’s first law of motion. b. (ii) Explain why many standing passengers tend to fall backward when the bus starts suddenly. c. (iii) Explain why the same passengers tend to fall forward when the bus brakes suddenly. d. (iv) Name one safety device fitted in motor vehicles that takes advantage of this law and describe briefly how it protects passengers in such situations.Intuitive explanation
This is about acceleration and deceleration—how velocity changes over time. When the driver starts the bus, they're applying a net force that increases velocity from zero; when braking, that force reverses direction, slowing the bus down. The key insight is that both scenarios involve non-zero acceleration, which you can find from or from Newton's second law . Understanding which direction the acceleration points (same as velocity when speeding up, opposite when slowing down) is crucial for solving real-world motion problems.
Intuitive explanation
This is about acceleration and deceleration—how velocity changes over time. When the driver starts the bus, they're applying a net force that increases velocity from zero; when braking, that force reverses direction, slowing the bus down. The key insight is that both scenarios involve non-zero acceleration, which you can find from or from Newton's second law . Understanding which direction the acceleration points (same as velocity when speeding up, opposite when slowing down) is crucial for solving real-world motion problems.