Units and Measurement
© examsnet.com
Question : 18
Total: 33
Explain this common observation clearly : If you look out of the window of a fast moving train, the nearby trees, houses etc. seem to move rapidly in a direction opposite to the train’s motion, but the distant objects (hill tops, the Moon, the stars etc.) seem to be stationary. (In fact, since you are aware that you are moving,. these distant objects seem to move with you).
Solution:
The line joining the object to the eye is called the line of sight. When atrain moves rapidly, the line of sight of a nearby tree changes its directionof motion rapidly i.e. near objects make greater angle than distant objects.Therefore the trees appear to run in opposite direction.
On the other hand, the angular change i.e. the line of sight of far off objects (hill tops, the moon, the stars etc.) changes its direction extremely slowlyand hence the relative shift in their position is negligible. Hence theyappear to be stationary i.e. move in the direction of the train i.e. appear tomove with the observer in the train.
On the other hand, the angular change i.e. the line of sight of far off objects (hill tops, the moon, the stars etc.) changes its direction extremely slowlyand hence the relative shift in their position is negligible. Hence theyappear to be stationary i.e. move in the direction of the train i.e. appear tomove with the observer in the train.
© examsnet.com
Go to Question: