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Question

A train starting from a railway station and moving with uniform acceleration attains a speed of $40km{h}^{-1}$ in $10minutes$. Find its acceleration in the units of $m{s}^{-2}$.

Solution

**Step 1: Given**

Initial speed, $u=0m{s}^{-2}$

Final velocity, $v=40km{h}^{-1}=40\times \frac{5}{18}=\frac{100}{9}m{s}^{-1}$

Time, $t=10minutes=600seconds$

**Step 2: Formula used and calculation**

Using the first equation of motion

$v=u+at\phantom{\rule{0ex}{0ex}}\Rightarrow \frac{100}{9}m{s}^{-1}=0+600s\times a\phantom{\rule{0ex}{0ex}}\Rightarrow a=\frac{100}{9\times 600}m{s}^{-2}\phantom{\rule{0ex}{0ex}}\Rightarrow a=0.0185m{s}^{-2}$

Hence, the acceleration of the train is $0.0185m{s}^{-2}$.

Physics

Standard VII

32

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