Question

A bus starts its journey from the terminal and moves with constant velocity 25 ms^-1. When reaching the junction of a road, the driver steps on the brake pedal and the bus stops after travelling a distance of 50 m. Calculate the deceleration of the bus after the brake is applied.

Answer 1

We can find the deceleration of the bus from the kinematic equation:

$$v^2=v_0^2+2ad,$$ $$a=\dfrac{v^2-v_0^2}{2d},$$ $$a=\dfrac{0-(25\ \dfrac{m}{s})^2}{2\cdot50\ m}=-6.25\ \dfrac{m}{s^2}.$$

The sign minus means that the bus decelerates.