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Question
Give the magnitude and direction of the net force acting on a stone of mass 0.1 kg, just after it is dropped from the window of a train accelerating with 1 m s–2. Neglect air resistance.
Solution
The stone will experience an additional force F’ (along horizontal), i.e.,F = ma = 0.1 x 1 = 0.1 N As the stone is dropped, the force F’ no longer acts, and the net force acting on the stone F = mg = 0.1 x 10 = 1.0 N (vertically downwards).
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