Question

A train is travelling at a speed of 90 km/h . Brakes are applied so as to produce a uniform acceleration of -0.5 m/s2. Find how far the train will go before it is brought to rest.

Answer 1

Explanation:

using equation

1. ${v }^{2} = {u}^{2} + 2as$
2. 0= 625-1s
3. s=625m

Answer 2

Answer:

Speed of train , u = 90 km/h = 90 × 5/18 = 25 m/s

acceleration , a = -0.5 m/s²

Use formula,

v = u + at

Finally train will be rest so, final velocity, v = 0

0 = 25 - 0.5t

25 = 0.5t ⇒t = 50 sec

Again, use formula,

S = ut + 1/2at²

Where S is distance travelled before stop

S = 25 × 50 - 1/2 × 0.5 × 50²

= 1250 - 1/2 × 0.5 × 2500

= 1250 - 625

= 625 m

Hence, distance travelled = 625m and time taken = 50 sec