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A train is travelling at a speed of 90 \text{ km h}^{-1}. Brak... - Science
Question
A train is travelling at a speed of 90 \text{ km h}^{-1}. Brakes are applied so as to produce a uniform acceleration of - 0.5 \text{ m s}^{-2}. Find how far the train will go before it is brought to rest.
Answer
Given:
Initial velocity (u) = 90 \text{ km/h} = 90 \times \frac{5}{18} = 25 \text{ m/s}
Final velocity (v) = 0 (since it comes to rest)
Acceleration (a) = -0.5 \text{ m/s}^2
Formula:
v^2 - u^2 = 2as
Calculation:
(0)^2 - (25)^2 = 2 \times (-0.5) \times s0 - 625 = -1 \times s-625 = -ss = 625 \text{ m}
Answer: The train will go 625 \text{ m} before it is brought to rest.