Which one among the following statements is not correct ?

Statement 2 is incorrect because Newton's law of universal gravitation is an empirical law derived from observations of planetary motion (Kepler's laws) and terrestrial gravity, rather than being a logical consequence of his laws of motion [1]. While the laws of motion describe how forces affect movement, the law of gravitation defines the specific nature of the gravitational force itself. Statement 1 is correct as the law states every particle in the universe attracts every other particle. Statement 3 is correct because, at the Earth's center, the gravitational pull from the surrounding mass cancels out in all directions, resulting in zero net acceleration. Statement 4 is correct as mass is measured in kilograms (kg) while weight, being a force, is measured in newtons (N) [3].

Sources

1. [1] https://imagine.gsfc.nasa.gov/observatories/learning/swift/classroom/docs/law_grav_guide.pdf
2. [3] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > A step further > p. 73