Question

Q. A bus is running at a speed of 18km/h is stopped in 2.5 seconds by applying brakes. Calculate the retardation produced.

Answer 1

The initial speed of the bus, u = 18 km/h = $\frac{18\times 1000}{60\times 60}=5\text{m/s}$
The final speed of the bus, v = 0
Time in which the bus stops, t = 2.5 s
Using the equation of motion:
v = u + at
⇒0 = 5 + a×2.5
⇒a = -5/2.5 = -2 m/s²