A train is travelling at a speed of 90 km h−1. Brakes are applied so as to produce a uniform acceleration of −0.5 m s−2. Find how far the train will go before it is brought to rest.
Initial speed of the train, u = 90 km/h = 25 m/s
Final speed of the train, v = 0 (finally the train comes to rest)
Acceleration = −0.5 m s−2
According to third equation of motion:
v2 = u2 + 2 as
(0)2 = (25)2 + 2 (−0.5) s
Where, s is the distance covered by the train
The train will cover a distance of 625 m before it comes to rest.