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STD 11 - 5. work,energy,power and collision — NEET STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceNEETSTD 11 - 5. work,energy,power and collision4 Marks
Question
A train is moving at a constant speed $V$. When its driver observes another train in front of him on the same track and moving in the same direction with constant speed $u$. If the distance between the trains be $x$, then what should be the minimum retardation of the train so as to avoid collision?
✓

Answer

Here relative velocity of the train $w.r.t.$ other

$\operatorname{train}=V-u$

Hence,

$0-(\mathrm{V}-\mathrm{u})^{2}=2 \mathrm{ax}$ or $\mathrm{a}=-\frac{(\mathrm{V}-\mathrm{u})^{2}}{2 \mathrm{x}}$

Minimum retardation $=\frac{(\mathrm{V}-\mathrm{u})^{2}}{2 \mathrm{x}}$

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