Question

The brakes applied to a train moving at 90km/h produces a retardation of 5 m/s². i) Calculate the time it takes to stop. ii) What distance will it cover before coming to a stop?

Answer 1

Answer:

A/q Initial speed = u = 90km/h = 90(5/18)

m/s = 25 m/s

Final speed = v = 0 Acceleration = a = -5 m/s sq.

Let the distance covered = s

Since, v2 = u2 + 2as

 0 = 25x25 +2x(-5)x s

 0 = 625 – 10s

 10s = 625  

s(distance will it cover before coming to a stop) = 62.5 m

Answer 2

Explanation:

A/q Initial speed = u = 90km/h = 90(5/18)

m/s = 25 m/s

Final speed = v = 0 Acceleration = a = -5 m/s sq.

Let the distance covered = s

Since, v2 = u2 + 2as

 0 = 25x25 +2x(-5)x s

 0 = 625 – 10s

 10s = 625 

s = 62.5 m