InterviewSolution
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InterviewSolution
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Given the magnitude and direction of the force acting on a stone of mass 0.1 kg (a) just after it is dropped from the window of a stationary train (b) just after it is dropped from the window of a train running at a constant velocity of `36 km//hr` (c) just after it is droped from the window of a train accelerating with `1 ms^(-2)` (d) lying on the floor of a trin which is accelerating with `1 ms^(-2)` the stone being at rest relative to the train . Neglect the resistance of air throuhout . |
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Answer» (a) Here ,`m = 0 .1 kg , a = + g = 10 m//s^(2)` Net force `F = ma = 0. 1 xx 10 = 1.0 N` This force acts vertically downwards . (b) When the train is runing at a constant velocity its acc = 0 No force acts on the stone due to this motion Therefore force on the stone F = mg ` = 0.1 xx 10 = 1.0 N` This force also acts vertically downwards (c) When the train is accelerating with `1 ms^(-2)` an additional Force `F = ma = 0.1 xx 1 = 0. 1` N acts on the stone in the horizontal direction But once the stone is dropped from tha train F becomes Zero and the net force on the stone is `F = mg = 0.1 xx 10 = 0.1 N` acting vertically downwards (d) As the stone is lying on the floor of the train its acceleration is same as that of the train `:.` force acting on stone ,`F = ma = 0.1 xx 1 = 0.1 N` This force is along the horizontal direction of motion of the train Note that weight of the stone in this case is being balanced by the normal reaction. |
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