Question #2544

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 s-2. Find how far the train will go before it is brought to rest .

Expert's answer

First find the time after which the train stops.

v=v_{0}-a*t=0, where v_{0}=90 km/h=90/3,6 m/s = 25m/s - initial velocity

v=0 the velocity when the train stops

t - time

Hence t=v_{0}/a=50 s

in that formula we take the module of a

The distance travelled s=v_{0}*t-a*sqr(t)/2

after substituting the value of t to the last formula we'll get the value of distance

s=625 m

v=v

v=0 the velocity when the train stops

t - time

Hence t=v

in that formula we take the module of a

The distance travelled s=v

after substituting the value of t to the last formula we'll get the value of distance

s=625 m

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