Q20 of 47 Page 8

A train is travelling at a speed of 90 km h-1. Brakes are applied so as to produce a uniform acceleration -0.5 ms-2. Find how far the train will go before it is brought to rest.

Initial speed, u = 90 km/h2

(Converting it into m/s, We know 1km=1000m and 1 hour= 3600 seconds)

=  

= 25 m/s

Final speed, v = 0 (As the train stops)

Acceleration, a = -0.5 m/s2(As the brakes are being applied the speed is reducing)

And,

Distance traveled, s =? (To be Calculated)

Now, v2 = u2 + 2as

(0)2 = (25)2 + 2 × (-0.5) × s

0 = 625 – 1 × s

0 = 625 - s

∴s = 625 m (Taking s on the other side will make it positive)

Therefore, 625 meters is the distance traveled by the train before it is brought to rest.

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