Sunday, May 17, 2009

Toss a coin in the moving train

Question:

Toss a coin in the moving train.... does it fall in your hand back...?

Answers:
1.most probably no because ven train is moving ur position cahnges n the path of coin is parabolic n with respect to ur position it falls at the pt where u actually had been at the time of throwin the coin 
its basically a relativity question . ur relative position changes bt coin has a tendency to fall down straight

2.well the coin already have the x component of vilocity 
i.e vilocity of coin in x direction = vilocity of the train 

well just think of this small case when ur going to stadium to play cricket
while on the street ur tossing the cricket ball a lil up and catch it as u walk
u defnately just gave the ball its y component 
its x component was already the vilocity of ur walk

now think of another case while u go in ur car on a highway 
after having a can of soft/hard drink u throw it out of the window 
u see the can falls straight 
but no wrt to earth its parabolic it was straight wrt to u ... 
(u can notice this effect better if u can do it from a helicoptor)

so for every single mm u moved ahead it followed u 
u would see diffrent result if u suddenly apply break 
u will reamin at ur postion while the can will drop ahead of u


so the moral of the story is if train is moving on a smooth track u wud defenately catch the coin back 

acc to observer on earth the path of coin will be parabolic

acc to observer on train the path of coin will be straight



3.it depends on the velocity of da train . 

wen train is moving wid uniform velocity ,it falls back into hand .
'" "" " wid acceleration , it falls behind him . 
" " " wid decelration , it falls in front of him.




4.ya always...because here the train is the reference frame and you and your coin is in rest with respect to this frame

exceptions will take place if the train suddenly starts accelerating or deccelerating while the coin has alredy been tossed and its in air due to inertia

am i not correct?? close your eyes and just think virtuall as if u are on the train this practicehelps a lot in tackeling mechanics

5. Ummmmmm...... There can be three cases.... I assume that the condition is ideal... Then the three case can be.

(i) When the train is in Uniform motion, the coin will return to his hands.
(ii) When the train is moving with a unform accelration, the ball will fall behind him.
(iii) When the train is moving with a uniform retardation, the ball will fall in front of him.


Note : All the cases assume that u r facing the direction in which the train is moving.





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