Question

(8 marks)
a) A train starts from rest and accelerates uniformly for 30 seconds to acquire a velocity
of 108 km/h. It travels with this velocity for 20 minutes. The driver now applies brakes
and the train slows down uniformly to stop after 20 seconds. Find the total distance
covered by the train.​

Answer 1

Explanation:

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Answer 2

Answer:

$36750 \: m$

Explanation:

When the train starts from rest,

u= 0,

t= 30s,

v= 108 km/h = 108 × 5/18 = 30 m/s.

Now,

a= v-u/t = 1 m/s².

Distance ,S1 = ut + 1/2 at²

= 0 + 1/2 × 1 × 30 × 30

= 450 m.

At uniform velocity of 30 m/s for 20 min, i.e., 1200s,

Distance, S2 = 30 × 1200 = 36000 m.

Now,

On applying brakes,

t= 20s,

u= 30 m/s,

v= 0.

a= v-u/t = 0-30/20 = -1.5 m/s²

Distance S3 = v² - u²/2a

= 0 - (30)² /2 × 1.5

= 300 m

Therefore,

The total distance traversed = S1 + S2 + S3

= (450 + 36000 + 300) m

= 36750 m