COMEDK · Physics · 3. Motion In One Dimension
A drone is flying due west, a little above the train, with a speed of \(10 \mathrm{~m} / \mathrm{s}\). A 270 meter long train is moving due east at a speed of \(20 \mathrm{~m} / \mathrm{s}\). The time taken by the drone to cross the train is
- A 13.5 s
- B 27 s
- C 20 s
- D 9 s
Answer & Solution
Correct Answer
(D) 9 s
Step-by-step Solution
Detailed explanation
Let the velocity of the drone be \(\vec{v}_{d} = -10 \hat{i} \text{ m/s}\) (due west). Let the velocity of the train be \(\vec{v}_{t} = 20 \hat{i} \text{ m/s}\) (due east). The relative velocity of the drone with respect to the train is…
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