##### 18. A train starts from rest and accelerates uniformly, until it has traveled 3

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 18 A train starts from rest and accelerates uniformly, until it has traveled 3.7 km and acquired a velocity of 30m/s The train then moves at a constant velocity of 30m/s for 410 s. The train then slows down uniformly at  0.065m/s^2until it reaches a halt. What distance does the train travel while it is slowing down?
May 18th, 2015

Distance covered when it slows down uniformly at 0.065m/s^2 until it reaches a halt is given by the equation

v2 = u2 + 2as

v = 30 m

u = 30 m/s

v = 0

a = -0.065

s = distance

0 = 900 - 0.13s

s = 6923.08 m = 6.9230 km.

May 18th, 2015

What distance does the train travel while it is slowing down?

Were are only concern with the distance covered by the train while it is slowing down, not total distance.

some clarification:

v2 = u2 + 2as

v is final velocity

u is initial velocity

a is acceleration

S is the distance

v = 0 ; since it will stop

u = 30 m/s; its initial velocity before decelerating.

a = -0.065 m/s2

so

o = 30^2 + 2(-0.065)s

-900 = -0.13s

s = 6923.08 meters or  6.92308 km.

Hope this helps. You can ask any question if you have any issue.

May 18th, 2015

Are you comfortable?

May 18th, 2015

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May 18th, 2015
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May 18th, 2015
May 29th, 2017
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