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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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