Question

A train travels at a speed of 64kmph. When it is 11Om away from an obstacle the
driver applies the break. Find the retardation so that train avoids the collision​

Answer 1

Given:-

→ Initial velocity of the train = 64km/h

→ Distance of the obstacle from the

train= 110m

To find:-

→ Required retardation of the train so that

it avoids collision.

Solution:-

Firstly, let's convert the initial velocity of the train from km/h to m/s.

=> 1km/h = 5/18m/s

=> 64km/h = 64×5/18

=> 17.78m/s [approximately]

In this case :-

• Final velocity of the train will be zero as it will finally come to rest after application of brakes.

Now, let's calculate the retardation by using the 3rd equation of motion:-

=> v² - u² = 2as

=> 0 - (17.78)² = 2×a×110

=> -316.12 = 220a

=> a = -316.12/220

=> a = -1.43m/s²

[Here, -ve sign shows retardation]

Thus, the train must have a retardation of 1.43m/s², so that it avoids the collision.