Question

A train is moving eastwards with a velocity of $10m/s$. On a parallel track another train passes with a velocity of $15m/s$ eastwards. To the passengers in the second train, the first train will appear to be moving with a velocity.

• A. $5m/s$ eastwards
• B. $25m/s$ eastwards
• C. $5m/s$ westwards
• D. $20m/s$ westwards

Answer 1

The correct option is C $5m/s$ westwards

Step 1: Draw the diagram as per the given information.

Step 2:
Find the velocity of $A$ with respect to $B$ $\left({\overrightarrow{V}}_{AB}\right)$.
${\overrightarrow{V}}_{AB}={\overrightarrow{V}}_A-{\overrightarrow{V}}_B$
${\overrightarrow{V}}_{AB}=10-15$
${\overrightarrow{V}}_{AB}=-5m/s$
Hence,
${\overrightarrow{V}}_{AB}=5m/s$ westwards.
Final Answer: (a)