Physics · Gravitation · NEET
They are related but not identical. Gravitation is the general force of attraction between ANY two masses anywhere in the universe (the Sun and Earth, two stars, or even two books). Gravity is the special case of this force between the Earth and an object near its surface. So gravity is one example of gravitation. For NEET, remember: gravitation is universal, gravity is Earth-specific.
No. This is the most common beginner mistake. Every object with mass pulls every other object. Your pen pulls your book, and you pull the person next to you. The Earth's pull is just very strong because the Earth's mass is huge (about 6 x 10^24 kg). Small objects pull each other too, but the force is far too weak to notice.
Because the gravitational force is extremely weak for small masses. The force follows F = G m1 m2 / r^2, and G is tiny (6.67 x 10^-11 N m^2/kg^2). For two 60 kg people 1 m apart, the pull is about 2.4 x 10^-7 N — far too small to feel. Only when one mass is planet-sized (like Earth) does the pull become noticeable.
Gravitation is always a pull (attractive), never a push. Two masses always try to come closer, never move apart because of gravitation. This is why the NEET 2017 astronaut question has the answer 'move towards each other' — in free space, with no other force, their own gravitation slowly pulls them together.
Isaac Newton gave the universal law of gravitation (published 1687). Before him, Galileo showed all bodies fall with the same acceleration, and Johannes Kepler described how planets orbit the Sun. Newton unified these ideas into one law: the same force that pulls an apple down also holds the Moon in orbit.
Two astronauts are floating in gravitational free space after losing contact with their spaceship. The two will:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Gravitation is the natural pull that any object with mass has on any other object with mass. It is the reason things fall down and the reason planets orbit the Sun.
Newton's law of gravitation is F = G m1 m2 / r^2, where m1 and m2 are the two masses, r is the distance between their centres, and G = 6.67 x 10^-11 N m^2/kg^2 is the universal gravitational constant.
Yes. Gravitation is a full chapter in NEET Physics and gives 1 to 2 questions almost every year, covering the universal law, g variation, escape velocity, satellites and Kepler's laws. Understanding this intro makes the whole chapter easier.
Because it acts everywhere and between all masses in the universe — from an apple and the Earth to two distant galaxies. The same single formula describes all of them, so it is called 'universal'.
Gravitation is only attractive. Unlike electric charges, masses never repel each other by gravitation — they always pull together.
