1.

Two parallel rail tracks run north-south. Train A moves north with a speed of 54 km h^(-1), and train B moves south with a speed of 90 km h^(-1). What is the (a) velocity of B with respect to A ?, (b) velocity of ground with respect to B ?, and (c) velocity of a monkey running on the roof of the train A against its motion (with a velocity of 18 km h^(-1) with respect to the train A) as observed by a man standing on the ground ?

Answer» <html><body><p></p>Solution :Choose the positive direction of x-axis to be from <a href="https://interviewquestions.tuteehub.com/tag/south-1219419" style="font-weight:bold;" target="_blank" title="Click to know more about SOUTH">SOUTH</a> to north. Then,<br/>`upsilon_(A)=+54 km h^(-<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>) = 15 ms^(-1)`<br/>`upsilon_(B)=-90 km h^(-1)=-25 ms^(-1)`<br/>Relative velocity of B with respect to `A=upsilon_(B)-upsilon_(A)=-<a href="https://interviewquestions.tuteehub.com/tag/40-314386" style="font-weight:bold;" target="_blank" title="Click to know more about 40">40</a> ms^(-1)`, i.e. the <a href="https://interviewquestions.tuteehub.com/tag/train-1425202" style="font-weight:bold;" target="_blank" title="Click to know more about TRAIN">TRAIN</a> B appears to A to move with a speed of 40 m s–1 from north to south. <br/>Relative velocity of ground with respect to<br/>`B=0-upsilon_(B)=25 ms^(-1)`.<br/>In (c), let the velocity of the monkey with respect to ground be `upsilon_(M)`. Relative velocity of the monkey with respect to A,<br/>`upsilon_(MA)=upsilon_(M)-upsilon_(A)=-18 km h^(-1)=-5 ms^(-1)`. Therefore, `upsilon_(M)=(15-5)ms^(-1)=<a href="https://interviewquestions.tuteehub.com/tag/10-261113" style="font-weight:bold;" target="_blank" title="Click to know more about 10">10</a> ms^(-1)`.</body></html>


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