Physics · 2013
JEE Main · 9 April 2013, Shift 1 · Q18
An engine approaches a hill with a constant speed. When it is at a distance of 0.9 km, it blows a whistle whose echo is heard by the driver after 5…
An engine approaches a hill with a constant speed. When it is at a distance of $\displaystyle 0.9$ km, it blows a whistle whose echo is heard by the driver after $\displaystyle 5$ seconds. If the speed of sound in air is $\displaystyle 330 \mathrm{~m} / \mathrm{s}$, then the speed of the engine is :
Official answer
(4)
$\displaystyle 30 \mathrm{~m} / \mathrm{s}$
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JEE Main 2013 Physics question, with the answer from NTA’s final answer key. Where our answers come from.