Physics, asked by Potatoooooo, 6 hours ago

two trains A and B are running is opposite direction on the same track with speed 20 m/s and 90km/h respectively. If the initial separation between them was 200 m then the time in seconds after which they collide is? ​

Answers

Answered by Anonymous
29

\qquad \qquad \rm \large {\underbrace{\underline{\dag{Elucidation:-}}}}

 \qquad \qquad \sf \red {\underline{\underline{\maltese{Provided:}}}}

➻Speed of train A is 20m/s

 \qquad \qquad \bf \to {V_{1}=20m/s}

➻Speed of train B is 90km/h

➻We need to convert the quantity to m/s.

➻In order to perform such conversation, the given value must be multiplied by the fraction  \sf {\frac{5}{18}}

 \qquad \qquad \tt \implies  {90×\frac{5}{18}}

 \qquad \qquad \tt \implies {\cancel{90}^{5}×\frac{5}{\cancel{18}}}

 \qquad \qquad \tt \implies {5×5}

 \qquad \qquad \bf \to {V_{2}=25m/s}

➻Distance between two trains is 200m

 \qquad \qquad \bf \to {S=200m}

 \qquad \qquad \sf \blue {\underline{\underline{\maltese{To\: Find:}}}}

➻The time in which they collide=?

 \qquad \qquad \bf \to {t=?}

 \qquad \qquad \sf \pink {\underline{\underline{\maltese{Formula:}}}}

 \qquad {\boxed{Speed=\frac{Distance}{Time}}}

 \qquad \qquad {\boxed{\boxed{V=\frac{S}{t}}}}

 \qquad \qquad \tt \to {But, V=?}

 \qquad \qquad \sf \purple {\underline{\underline{\maltese{We\: Know:}}}}

 \qquad  \tt  \to {Relative\: Speed=V_{1}+V_{2}}

 \qquad \qquad  \tt  \implies {V=20+25}

 \qquad \qquad  \tt  \implies {V=45m/s}

➻Now, substituting in the formula,

 \qquad \qquad \tt \to {V=\frac{S}{t}}

 \qquad \qquad \tt \implies {45m/s=\frac{200m}{t}}

 \qquad \qquad \tt \implies {t=\frac{200}{45}}

 \qquad \qquad \tt \implies {t=4.44}

 \qquad \qquad  \tt \implies \green {\boxed{\underline{t=4.5 sec}}}

 \qquad \qquad \sf \orange {\underline{\underline{\maltese{Henceforth,}}}}

➻The time in which the two trains collide is "4.5 Seconds" respectively.

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