Two masses 10 cm apart, attract each other with a force,f Newtons. When 5 cm apart, these masses will attract each other with a force (in Newtons) of:
Correct answer: C. 4f
- A. f/2
- B. f/4
- C. 4f
- D. 2f
Explanation
The gravitational force between two masses is given by Newton's law of gravitation, f= GMm/ r 2 Initially, the distance was 10cm so f= GMm/ (10 cm )2 As the separation between them decreased to 5 cm, the new force f' became = GMm/ (5 cm )2 On comparing both the forces, their ratio is equal to, f'/f= 4/1 So the correct option is C.
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Newton’s law of universal gravitation relates the force between masses to their masses and separation, while gravitational field strength explains weight and orbital motion. The topic covers satellite velocity and period, escape ideas, weightlessness in free fall, and artificial gravity, which differs from ordinary gravitational attraction.
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