A train starts from rest with an acceleration of 0.5 $ms^{-2}$. Find its speed in $kmh^{-1}$, when it has moved through 100 m. $(36kmh^{-1})$
Difficulty: Easy
Solution:
Initial velocity Vi = 0 $ms^{-1}$
Acceleration a = $0.5 ms^{-2}$
Distance S = 100 m
Final velocity Vf =?
2aS = $Vf^{2} – Vi^{2}$
$2 \times 0.5 \times 100 = Vf^{2}$ – 0
Or 100 = $Vf^{2}$
Or
$Vf^{2} = 100 ms^{-1}$……………………..(I)
Speed in $kmh^{-1}$:
From (I) we get;
Vf = $10 \times \frac{3600}{1000}= 36 kmh^{-1}$
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